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1. The phase function and density of the dust observed at comet 67P/Churyumov-Gerasimenko

Author: P. J. Gutierrez, W-H. Ip, F. Moreno, Monica Lazzarin, F. La Forgia, Ivano Bertini, Xian Shi, V. Da Deppo, Cesare Barbieri, Stefano Mottola, Holger Sierks, Giampiero Naletto, Pasquale Palumbo, M. A. Barucci, Jakob Deller, Stavro Ivanovski, H. S. Hviid, J. Lasue, Giovanna Rinaldi, Marco Fulle, Michael Küppers, Philippe Lamy, Hans Rickman, Stefano Debei, Ekkehard Kührt, Alessandra Rotundi, Detlef Koschny, Nicolas Thomas, R. Rodrigo, M. De Cecco, J.-R. Kramm, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, G. Cremonese, Carsten Güttler, J. L. Bertaux, Anny Chantal Levasseur-Regourd, M. L. Lara, Olivier Groussin, Sonia Fornasier, Jörg Knollenberg, V. Della Corte, J. J. López-Moreno, H. U. Keller, Francesco Marzari, Dennis Bodewits, Agenzia Spaziale Italiana, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], INAF - Osservatorio Astronomico di Trieste ( OAT ), Istituto Nazionale di Astrofisica ( INAF ), Istituto di Astrofisica e Planetologia Spaziali ( IAPS ), Dipartimento di Scienze e Tecnologie [Napoli] ( DIST ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), International Space Science Institute ( ISSI ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Laboratory for Ultraviolet and X-ray Optical Research [Padova] ( LUXOR ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ) -Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), National Central University [Taiwan] ( NCU ), Space Science Institute [Macau] ( SSI ), Macau University of Science and Technology ( MUST ), Aix Marseille Université ( AMU ), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] ( IGEP ), and European Space Astronomy Center ( ESAC )
Subjects: 67P/Churyumov-Gerasimenko, Brightness, comets: individual: 67P/Churyumov- Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Dust particles, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, space vehicles, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, 01 natural sciences, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Phase function, Astrophysics::Solar and Stellar Astrophysics, comets, Particle density, 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, 520 Astronomy, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, general [Comets], Astronomy and Astrophysics, Space vehicles, 620 Engineering, Bulk density, space vehicles, comets: general, comets: individual: 67P/Churyumov- Gerasimenko, Density distribution, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], space vehicles, Astrophysics::Earth and Planetary Astrophysics, Mass fraction
Abstract: The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observed close to Rosetta by OSIRIS, occurring about every hour, consistent with the fragmentation on impact with Rosetta of parent particles, whose flux agrees with the dust flux observed by GIADA. OSIRIS also measured the antisunward acceleration of the fragments, thus providing the first direct measurement of the solar radiation force acting on the dust fragments and thus of their bulk density, excluding any measurable rocket effect by the ice sublimation from the dust. The obtained particle density distribution has a peak matching the bulk density of most COSIMA particles, and represents a subset of the density distribution measured by GIADA. This implies a bias in the elemental abundances measured by COSIMA, which thus are consistent with the 67P dust mass fractions inferred by GIADA, i.e. (38 ± 8) per cent of hydrocarbons versus the (62 ± 8) per cent of sulphides and silicates.© 2018 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society., We thank the anonymous referee for having significantly improved the paper; and the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. All GIADA data presented here are available on request before archiving in the PSA. This research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0 and I/024/12/0.
Published: 2018

2. Adaptive Deadlock Control for a Class of Petri Nets With Unreliable Resources

Author: Zhiwu Li, Kamel Barkaoui, Gaiyun Liu, Ziliang Zhang, Xidian University, CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), and Macau University of Science and Technology (MUST)
Subjects: Class (computer programming), Theoretical computer science, Computer science, Deadlock, Petri net, Computer Science Applications, Human-Computer Interaction, [SPI]Engineering Sciences [physics], Control and Systems Engineering, [INFO]Computer Science [cs], Electrical and Electronic Engineering, Control (linguistics), ComputingMilieux_MISCELLANEOUS, Software
Abstract: International audience
Published: 2022

3. Sums of even ascending powers

Author: Kuan, Chan Ieong, Lesesvre, Didier, Xiao, Xuanxuan, Sun Yat-Sen University [Guangzhou] (SYSU), Université de Lille, and Macau University of Science and Technology (MUST)
Subjects: Mathematics - Number Theory, FOS: Mathematics, 11P05, 11P55, Number Theory (math.NT), [MATH.MATH-NT]Mathematics [math]/Number Theory [math.NT]
Abstract: Freiman and Scourfield proved that any large enough integer can be written as a sum of a certain number of ascending even powers. We use the circle method to provide the first explicit bound on this number, and show that any large enough integer can be written as a sum of 133 ascending even powers., Comment: 20 pages
Published: 2022

4. Exploiting local persistency for reduced state-space generation

Author: Zhiwu Li, Hanifa Boucheneb, Kamel Barkaoui, CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), École Polytechnique de Montréal (EPM), and Macau University of Science and Technology (MUST)
Subjects: Set (abstract data type), Computer science, 020204 information systems, 0202 electrical engineering, electronic engineering, information engineering, [INFO]Computer Science [cs], 020207 software engineering, 02 engineering and technology, Petri net, State space generation, Algorithm, ComputingMilieux_MISCELLANEOUS, Software, Parametric statistics
Abstract: This paper deals with the partial order techniques of Petri nets, based on persistent sets and step graphs. To take advantage of the strengths of each method, it proposes the persistent step sets as a parametric combination of the both methods. The persistent step sets method allows to fix, for each marking, the set of transitions to be covered by the selected steps and then to control their maximal length and number. Moreover, this persistent step selective search preserves, at least, deadlocks of Petri nets.
Published: 2020

5. Computation of an emptiable minimal siphon in a subclass of petri nets using mixed-integer programming

Author: Xin Guo, Xiaoning Jiang, Wenli Duo, Shouguang Wang, Kamel Barkaoui, Dan You, MengChu Zhou, Zhejiang Gongshang University [Hangzhou] (ZJSU), Macau University of Science and Technology (MUST), CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), and New Jersey Institute of Technology [Newark] (NJIT)
Subjects: 0209 industrial biotechnology, Computational complexity theory, Computer science, Computation, Liveness, 02 engineering and technology, Parallel computing, Petri net, 020901 industrial engineering & automation, Deadlock resolution, Artificial Intelligence, Control and Systems Engineering, 0202 electrical engineering, electronic engineering, information engineering, Enumeration, [INFO]Computer Science [cs], 020201 artificial intelligence & image processing, Siphon, [MATH]Mathematics [math], Integer programming, ComputingMilieux_MISCELLANEOUS, Information Systems
Abstract: Deadlock resolution strategies based on siphon control are widely investigated. Their computational efficiency largely depends on siphon computation. Mixed-integer programming &#x0028 MIP &#x0029 can be utilized for the computation of an emptiable siphon in a Petri net &#x0028 PN &#x0029 . Based on it, deadlock resolution strategies can be designed without requiring complete siphon enumeration that has exponential complexity. Due to this reason, various MIP methods are proposed for various subclasses of PNs. This work proposes an innovative MIP method to compute an emptiable minimal siphon &#x0028 EMS &#x0029 for a subclass of PNs named S4PR. In particular, many particular structural characteristics of EMS in S4PR are formalized as constraints, which greatly reduces the solution space. Experimental results show that the proposed MIP method has higher computational efficiency. Furthermore, the proposed method allows one to determine the liveness of an ordinary S4PR.
Published: 2020

6. Fourier DF unit root test for R&D intensity of G7 countries

Author: Jamel Saadaoui, Yifei Cai, Macau University of Science and Technology (MUST), Bureau d'Économie Théorique et Appliquée (BETA), Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)
Subjects: History, Intensité de R&D, Fourier Dickey-Fuller unit root test, Polymers and Plastics, Double fréquence, Sample (statistics), Modèle de croissance schumpérien, Industrial and Manufacturing Engineering, symbols.namesake, Schumpeterian growth model, 0502 economics and business, Econometrics, 050207 economics, Business and International Management, Double frequency, 050205 econometrics, Mathematics, R&D intensity, Endogenous growth theory, Series (mathematics), 05 social sciences, JEL: C - Mathematical and Quantitative Methods/C.C1 - Econometric and Statistical Methods and Methodology: General/C.C1.C12 - Hypothesis Testing: General, JEL: C - Mathematical and Quantitative Methods/C.C2 - Single Equation Models • Single Variables/C.C2.C22 - Time-Series Models • Dynamic Quantile Regressions • Dynamic Treatment Effect Models • Diffusion Processes, Test de racine unitaire de Fourier Dickey-Fuller, [SHS.ECO]Humanities and Social Sciences/Economics and Finance, Fourier transform, Unit root test, 8. Economic growth, symbols, Unit root, JEL: O - Economic Development, Innovation, Technological Change, and Growth/O.O3 - Innovation • Research and Development • Technological Change • Intellectual Property Rights/O.O3.O30 - General, JEL: O - Economic Development, Innovation, Technological Change, and Growth/O.O4 - Economic Growth and Aggregate Productivity/O.O4.O40 - General, Intensity (heat transfer)
Abstract: International audience; According to the Schumpeterian endogenous growth theory, the efficacy of R&D is lowered by the proliferation of products. To be consistent with empirical data, the ratio between innovative activity and product variety (also called R&D intensity) must be stationary. In this perspective, our contribution investigates whether the R&D intensity series are stationary when structural breaks are considered. Our sample of G7 countries is examined over the period spanning from 1870 to 2016. Our results indicate that traditional unit root tests (ADF, DF-GLS and KPSS) conclude that the R&D intensity series are non-stationary in contradiction with the Schumpeterian endogenous growth theory. The conclusions of these traditional unit root tests may be misleading, as they ignore the presence of structural breaks. Indeed, we use several types of Fourier Dickey-Fuller tests to consider the presence of structural breaks. In the Fourier Dickey-Fuller unit root tests using double frequency and fractional frequency, the R&D intensity is significantly stationary at least at the 5% level for Canada, France, Germany, Italy, Japan and the UK when a deterministic trend is included in the tests. Nevertheless, the R&D intensity is non-stationary for the US, even when we consider structural breaks. Indeed, the integration analyses aimed at discriminating between competing theories of endogenous growth should be careful of the presence of structural breaks. Especially when historical data are used, traditional unit root tests may lead to erroneous economic interpretations. These findings may help to understand the true nature of long-run economic growth and may help to formulate sound policy recommendations.; Selon la théorie schumpéchéenne de la croissance endogène, l’efficacité de la R&D est réduite par la prolifération des produits. Pour être cohérent avec les données empiriques, le rapport entre l’activité d’innovation et la variété des produits (aussi appelé intensité de R-D) doit être stationnaire. Dans cette perspective, notre contribution examine si les séries d’intensité de R-D sont stationnaires lorsque les ruptures structurelles sont prises en compte. Notre échantillon de pays du G7 est examiné au cours de la période allant de 1870 à 2016. Nos résultats indiquent que les tests de racines unitaires traditionnels (ADF, DF-GLS et KPSS) concluent que les séries d’intensité de R&D sont non stationnaires en contradiction avec la théorie de la croissance endogène schumpérienne. Les conclusions de ces tests de racines unitaires traditionnels peuvent être trompeuses, car elles ignorent la présence de ruptures structurelles. En effet, nous utilisons plusieurs types de tests de Fourier Dickey-Fuller pour considérer la présence de ruptures structurelles. Dans les essais de base unitaire de Fourier Dickey-Fuller utilisant la fréquence double et la fréquence fractionnaire, l’intensité de R-D est significativement stationnaire au moins au niveau de 5 % pour le Canada, la France, l’Allemagne, l’Italie, le Japon et le Royaume-Uni lorsqu’une tendance déterministe est incluse dans les essais. Néanmoins, l’intensité de la R&D n’est pas stationnaire pour les États-Unis, même si l’on considère les ruptures structurelles. En effet, les analyses d’intégration visant à distinguer entre les théories concurrentes de la croissance endogène doivent faire attention à la présence de ruptures structurelles. En particulier lorsque des données historiques sont utilisées, les tests de racine unitaire traditionnels peuvent conduire à des interprétations économiques erronées. Ces résultats peuvent aider à comprendre la véritable nature de la croissance économique à long terme et peuvent aider à formuler des recommandations politiques judicieuses.
Published: 2021

7. Possible Deep Structure and Composition of Venus With Respect to the Current Knowledge From Geodetic Data

Author: Jean-Pierre Barriot, Chi Xiao, Fei Li, Jianguo Yan, Yuji Harada, Weifeng Hao, Michel Grégoire, Mao Ye, Wuhan University [China], Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Macau University of Science and Technology (MUST), Géopôle du Pacifique Sud (GePaSUD), Université de la Polynésie Française (UPF), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Basalt, 010504 meteorology & atmospheric sciences, Spacecraft, biology, business.industry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Geodetic datum, Boundary (topology), Venus, Geophysics, 010502 geochemistry & geophysics, biology.organism_classification, 01 natural sciences, Mantle (geology), Boundary layer, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Planet, Earth and Planetary Sciences (miscellaneous), business, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Almost no in situ seismic data are available for Venus; therefore, we can constrain the deep structure of this planet only from the geodetic data obtained by spacecraft. Of particular interest is Venus's core-mantle boundary, which holds clues about the origin and evolution of this celestial body. In this study, we build a series of different mantle/core models of Venus based on several mantle composition models and compare their associated Love numbers k2 with the observed values. Due to the large uncertainty in the observed values of k2, the state of Venus's core cannot be reliably constrained. However, the expected precision of k2 obtained by the EnVision mission will sufficiently reduce the acceptable model space and contribute to estimating the mantle viscosity structure. Based on current geodetic data, we find that the bottom of Venus's mantle may not feature a phase transition from perovskite to post-perovskite if the FeO content of the mantle is less than 8.1 wt%; this region may be different from Earth's D” layer. Furthermore, we find that the combination of observed k2 and Q can be used to distinguish whether the lowermost part of Venus's mantle is a high-temperature basalt layer or a thin thermal boundary layer if observations of Q can be obtained.
Published: 2021

8. Multimodal GANs: Toward Crossmodal Hyperspectral–Multispectral Image Segmentation

Author: Deyu Meng, Danfeng Hong, Jing Yao, Jocelyn Chanussot, Zongben Xu, GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Xi'an Jiaotong University (Xjtu), Macau University of Science and Technology (MUST), Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Chinese Academy of Sciences [Beijing] (CAS), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Apprentissage de modèles à partir de données massives (Thoth), Inria Grenoble - Rhône-Alpes, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK)
Subjects: Computer science, multispectral (MS), Multispectral image, Feature extraction, 0211 other engineering and technologies, 02 engineering and technology, remote sensing, deep learning (DL), Robustness (computer science), 0202 electrical engineering, electronic engineering, information engineering, Overhead (computing), Segmentation, Electrical and Electronic Engineering, single image training, 021101 geological & geomatics engineering, convolutional neural network (CNN), business.industry, hyperspectral (HS), Hyperspectral imaging, generative adversarial networks (GANs), Pattern recognition, Image segmentation, cross modality, Classification, semantic segmentation, Feature (computer vision), General Earth and Planetary Sciences, 020201 artificial intelligence & image processing, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; This article addresses the problem of semantic segmentation with limited cross-modality data in large-scale urban scenes. Most prior works have attempted to address this issue by using multimodal deep neural networks (DNNs). However, their ability to effectively blending different properties across multimodalities and robustly learning representations from complex scenes remains limited, particularly in the absence of sufficient and well-annotated training images. This leads to a challenge related to cross-modality learning with multimodal DNNs. To this end, we introduce two novel plug-and-play units in the network: self-generative adversarial networks (GANs) module and mutual-GANs module, to learn perturbation-insensitive feature representations and to eliminate the gap between multimodalities, respectively, yielding more effective and robust information transfer. Furthermore, a patchwise progressive training strategy is devised to enable effective network learning with limited samples. We evaluate the proposed network on two multimodal (hyperspectral and multispectral) overhead image data sets and achieve a significant improvement in comparison with several state-of-the-art methods.
Published: 2021

9. Nanostructured Dense Collagen-Polyester Composite Hydrogels as Amphiphilic Platforms for Drug Delivery

Author: Olivier Ronsin, Basile Gravez, Xiaolin Wang, Christophe Hélary, Tristan Baumberger, Frederic Jaisser, Thibaud Coradin, Nicolette Farman, Gestionnaire, Hal Sorbonne Université, Macau University of Science and Technology (MUST), Matériaux et Biologie (LCMCP-MATBIO), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Mécanique multi-échelles des solides faibles (INSP-E7), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche des Cordeliers (CRC (UMR_S_1138 / U1138)), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Université Paris Cité (UPCité), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Université de Paris (UP)
Subjects: collagen, dense hydrogels, General Chemical Engineering, [SDV]Life Sciences [q-bio], General Physics and Astronomy, Medicine (miscellaneous), 02 engineering and technology, In Vitro Techniques, Spironolactone, polyesters, 010402 general chemistry, 01 natural sciences, Biochemistry, Genetics and Molecular Biology (miscellaneous), composites, in situ nanoprecipitation, Surface-Active Agents, chemistry.chemical_compound, Drug Delivery Systems, Tissue engineering, Amphiphile, Collagen network, drug delivery system, General Materials Science, lcsh:Science, Full Paper, Chemistry, General Engineering, technology, industry, and agriculture, Hydrogels, Full Papers, 021001 nanoscience & nanotechnology, Nanostructures, 0104 chemical sciences, Polyester, [SDV] Life Sciences [q-bio], PLGA, Chemical engineering, Drug delivery, Self-healing hydrogels, Polycaprolactone, lcsh:Q, 0210 nano-technology
Abstract: Associating collagen with biodegradable hydrophobic polyesters constitutes a promising method for the design of medicated biomaterials. Current collagen‐polyester composite hydrogels consisting of pre‐formed polymeric particles encapsulated within a low concentrated collagen hydrogel suffer from poor physical properties and low drug loading. Herein, an amphiphilic composite platform associating dense collagen hydrogels and up to 50 wt% polyesters with different hydrophobicity and chain length is developed. An original method of fabrication is disclosed based on in situ nanoprecipitation of polyesters impregnated in a pre‐formed 3D dense collagen network. Composites made of poly(lactic‐co‐glycolic acid) (PLGA) and poly(lactic acid) (PLA) but not polycaprolactone (PCL) exhibit improved mechanical properties compared to those of pure collagen dense hydrogels while keeping a high degree of hydration. Release kinetics of spironolactone, a lipophilic steroid used as a drug model, can be tuned over one month. No cytotoxicity of the composites is observed on fibroblasts and keratinocytes. Unlike the incorporation of pre‐formed particles, the new process allows for both improved physical properties of collagen hydrogels and controlled drug delivery. The ease of fabrication, wide range of accessible compositions, and positive preliminary safety evaluations of these collagen‐polyesters will favor their translation into clinics in wide areas such as drug delivery and tissue engineering., In situ nanoprecipitation of biocompatible and biodegradable polyesters within a preformed‐3D collagen network enables the synthesis of nanostructured dense collagen‐polyester composite hydrogels. Modulation of polyester hydrophobicity and chain length allows for both improved physical properties of collagen hydrogels and controlled drug release. Hence, the as‐obtained composite hydrogels represent a novel platform for drug delivery and tissue engineering applications.
Published: 2021

10. Mare basalt flooding events surrounding Chang'e-4 landing site as revealed by Zhinyu crater ejecta

Author: Zhanchuan Cai, Roberto Bugiolacchi, Sheng Gou, Kaichang Di, Zongyu Yue, Patrick Pinet, Meng-Hua Zhu, Macau University of Science and Technology (MUST), University College of London [London] (UCL), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Von Kármán crater, Magma chamber, engineering.material, 01 natural sciences, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Impact crater, Zhinyu crater, 0103 physical sciences, Homogenous composition, Ejecta, Petrology, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Basalt, Olivine, Single magma chamber, Flooding (psychology), Astronomy and Astrophysics, Mare flooding, 13. Climate action, Space and Planetary Science, Magma, engineering, Period (geology), Geology
Abstract: International audience; Von Kármán crater's floor was flooded with mare basalts during the Imbrian period. This site is the target of China's ongoing Chang'e-4 mission that includes the Yutu-2 rover and its instrumental payload. The Zhinyu crater, one of the largest craters within a few tens of kilometers from the landing site, is the product of a fresh impact that excavated subsurface, basaltic materials onto the surface. The compositional characteristics of the continuous ejecta around the crater vary radially with distance, suggesting possible mineral heterogeneity at depth. At least three main mare flooding phases could have occurred within Von Kármán, producing a basalt layer of at least 320 m in thickness. However, a broadly consistent olivine composition (Fo#: 55) of the three proposed basalt layers suggests that the sources of the mare basalts would have been similar in composition, perhaps even consisting of a single magma chamber where magma had time to evolve. The Yutu-2 rover that is edging its way westwards, could in principle test this hypothesis, thus further constraining the thermal history of the Von Kármán crater.
Published: 2021

11. Time based deadlock prevention for Petri nets

Author: Boucheneb, Hanifa, Barkaoui, Kamel, Xing, Qian, Wang, Kuangze, Liu, Gaiyun, Li, Zhiwu, École Polytechnique de Montréal, Montréal, Canada, CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), Xidian University, and Macau University of Science and Technology (MUST)
Subjects: 0209 industrial biotechnology, 020901 industrial engineering & automation, Control and Systems Engineering, 0202 electrical engineering, electronic engineering, information engineering, [INFO]Computer Science [cs], 020207 software engineering, 02 engineering and technology, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2022

12. Cross-Attention in Coupled Unmixing Nets for Unsupervised Hyperspectral Super-Resolution

Author: Xiao Xiang Zhu, Danfeng Hong, Jocelyn Chanussot, Jing Yao, Deyu Meng, Zongben Xu, School of Mathematics and Statistics, Xi’an Jiaotong University, Xi'an Jiaotong University (Xjtu), German Aerospace Center (DLR), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Apprentissage de modèles à partir de données massives (Thoth), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Macau University of Science and Technology (MUST), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), and Technical University of Munich (TUM)
Subjects: FOS: Computer and information sciences, Computer science, Computer Vision and Pattern Recognition (cs.CV), multispectral, Multispectral image, Computer Science - Computer Vision and Pattern Recognition, 0211 other engineering and technologies, 02 engineering and technology, hyperspectral super-resolution, Consistency (database systems), Coupled unmixing, FOS: Electrical engineering, electronic engineering, information engineering, 0202 electrical engineering, electronic engineering, information engineering, unsupervised, Image resolution, 021101 geological & geomatics engineering, EO Data Science, cross-attention, Basis (linear algebra), business.industry, Deep learning, Image and Video Processing (eess.IV), Hyperspectral imaging, deep learning, Pattern recognition, Electrical Engineering and Systems Science - Image and Video Processing, Autoencoder, 020201 artificial intelligence & image processing, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; The recent advancement of deep learning techniques has made great progress on hyperspectral image super-resolution (HSI-SR). Yet the development of unsupervised deep networks remains challenging for this task. To this end, we propose a novel coupled unmixing network with a cross-attention mechanism, CUCaNet for short, to enhance the spatial resolution of HSI by means of higher-spatial-resolution multispectral image (MSI). Inspired by coupled spectral unmixing, a two-stream convolutional autoencoder framework is taken as backbone to jointly decompose MS and HS data into a spectrally meaningful basis and corresponding coefficients. CUCaNet is capable of adaptively learning spectral and spatial response functions from HS-MS correspondences by enforcing reasonable consistency assumptions on the networks. Moreover, a cross-attention module is devised to yield more effective spatial-spectral information transfer in networks. Extensive experiments are conducted on three widely-used HS-MS datasets in comparison with state-of-the-art HSI-SR models, demonstrating the superiority of the CUCaNet in the HSI-SR application. Furthermore, the codes and datasets are made available at: https://github.com/danfenghong/ECCV2020_CUCaNet.
Published: 2020

13. Hardy-Hodge decomposition of vector fields on compact Lipschitz hypersurfaces

Author: Baratchart, Laurent, Pei, Dang, Qian, Tao, Analyse fonctionnelle pour la conception et l'analyse de systèmes (FACTAS), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Macau University of Science and Technology (MUST), and Baratchart, Laurent
Subjects: boundary value problems, Helmholtz-Hodge decomposition, [MATH] Mathematics [math], [MATH]Mathematics [math], harmonic gradients, Clifford analysis
Abstract: For M a compact Lipschitz Riemannian manifold of dimension at least 2, we prove a Helmholtz-Hodge decomposition of tangent $L p$ vector fields as a sum of a gradient and a divergence free fields; the result holds for restricted range of p around 2, and for all $p ∈ (1, ∞)$ when M is V M O-smooth. If, moreover, M is a compact and connected hypersurface having the local Lipschitz graph property, embedded in $R n+1$ with the natural metric, we also establish a Hardy-Hodge decomposition of a $R n+1$-valued vector field of L p class on M as the sum of a tangent divergence free field and of two (traces of) harmonic gradients of Hardy class with exponent p, one from inside and one from outside M. The latter holds for restricted range of p, and for all $p ∈ (1, ∞)$ when M is $C 1$-smooth.
Published: 2020

14. Observer-based output feedback robust MPC via zonotopic set-membership state estimation for LPV systems with bounded disturbances and noises

Author: Sen Yang, Xubin Ping, Baocang Ding, Zhiwu Li, Tarek Raïssi, School of Electronic Engineering [Xidian University] (SEE), Xidian University, Chongqing University of Posts and Telecommunications, CEDRIC. Traitement du signal et architectures électroniques (CEDRIC - LAETITIA), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), and Macau University of Science and Technology (MUST)
Subjects: 0209 industrial biotechnology, Optimization problem, Computer Networks and Communications, Computer science, Applied Mathematics, 020208 electrical & electronic engineering, 02 engineering and technology, Invariant (physics), Ellipsoid, [SPI.AUTO]Engineering Sciences [physics]/Automatic, Model predictive control, [SPI]Engineering Sciences [physics], 020901 industrial engineering & automation, Control and Systems Engineering, Control theory, Bounded function, Signal Processing, 0202 electrical engineering, electronic engineering, information engineering, State observer, Robust control, Scaling, ComputingMilieux_MISCELLANEOUS
Abstract: For linear parameter varying (LPV) systems with bounded disturbances and noises, this paper presents a synthesis approach to observer-based output feedback robust model predictive control (RMPC) via the zonotopic set-membership state estimation. In the off-line optimization problem, the state observer sub-gains with a minimal ellipsoidal robust positively invariant (RPI) set for the zonotopic estimation error set are designed. In the on-line control optimization problem, bounds of the current and future zontopic estimation error sets are outer approximated by scaling the minimal ellipsoidal RPI set. Then, an on-line constrained optimization problem that considers bounds of the predicted zonotopic estimation error sets is solved to guarantee robust stability of the closed-loop observer system. In the on-line receding horizon optimization, the zonotopic estimation error set is refreshed based on zonotopic properties, and its outer approximated ellipsoidal set is optimized via the technique of S-procedure. By properly considering the relationship between the zonotopic estimation error set and its outer approximated ellipsoidal set, recursive feasibility of the optimization problem can be ensured. The on-line optimization problem guarantees that the nominal estimation error system and nominal closed-loop observer system converge to the origin. When bounded disturbances and noises are considered, the estimation error system and closed-loop observer system respectively bounded within time-varying RPI sets and robust control invariant (RCI) sets are steered to a neighborhood of the origin such that robust stability of the controlled system is guaranteed. A simulation example is given to illustrate the proposed method.
Published: 2020

15. Geochemistry, geochronology and petrogenesis of Maya Block granitoids and dikes from the Chicxulub Impact Crater, Gulf of México: Implications for the assembly of Pangea

Author: Zhao, Jiawei, Xiao, Long, Gulick, Sean P.S., Morgan, Joanna, Kring, David, Fucugauchi, Jaime Urrutia, Schmieder, Martin, de Graaff, Sietze, Wittmann, Axel, ROSS, Catherine, Claeys, Philippe, Pickersgill, Annemarie, Kaskes, Pim, Goderis, Steven, Rasmussen, Cornelia, Vajda, Vivi, Ferrière, Ludovic, Feignon, Jean–Guillaume, Chenot, Elise, Sato, Honami, Yamaguchi, Kosei, J. Bralower, Timothy, Christeson, Gail l., Cockell, Charles S., Coolen, Marco J.L., Gebhardt, Catalina, Goto, Kazuhisa, Green, Sophie, Jones, Heather, LeBer, Erwan, LOFI, Johanna, Lowery, Christopher, OCAMPO-TORRES, Ruben, Perez-Cruz, Ligia, Poelchau, Michael H., Rae, Auriol S.P., Rebolledo-Vieyra, Mario, Riller, Ulrich, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Whalen, Michael T., Chemistry, Analytical, Environmental & Geo-Chemistry, Faculty of Sciences and Bioengineering Sciences, Earth System Sciences, Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), State Key Laboratory of Geological Processes and Mineral Resources [Wuhan] (GPMR), China University of Geosciences [Wuhan] (CUG), State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Institute of Geophysics [Austin] (IG), University of Texas at Austin [Austin], Department of Earth Science and Engineering [Imperial College London], Imperial College London, Lunar and Planetary Institute [Houston] (LPI), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Arizona State University [Tempe] (ASU), Eyring Materials Center for Solid State Science, School of Geographical and Earth Sciences [Univ Glasgow], University of Glasgow, NERC Argon Isotope Facility [Glasgow], Scottish Universities Environmental Research Centre (SUERC), University of Glasgow-University of Edinburgh-University of Glasgow-University of Edinburgh-Natural Environment Research Council (NERC), Department of Geology and Geophysics, University of Utah, Department of Palaeobiology [Stockholm], Swedish Museum of Natural History (NRM), Natural History Museum [Vienna] (NHM), Department of Lithospheric Research [Wien], Universität Wien, Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Department of Chemistry, Toho University, and Study funded by the National Natural Science Foundation of China (41772050, 41830214, 41773061), MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (MSFGPMR05) and the Science andTechnology Development Fund (FDCT) of Macau (Grant No. 121/2017/A3).
Subjects: Felsite, 010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Annan geovetenskap och miljövetenskap, Geology, Orogeny, Pangea, 010502 geochemistry & geophysics, Anatexis, 01 natural sciences, Continental arc, Peri–Gondwanan realm, Gondwana, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU]Sciences of the Universe [physics], Geochronology, Chicxulub impact crater, Slab breakoff, Laurentia, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Petrogenesis, Other Earth and Related Environmental Sciences
Abstract: 23 pages; International audience; The Late Paleozoic tectono–magmatic history and basement of the Maya block are poorly understood due to the lack of exposures of coeval magmatic rocks in the region. Recently, IODP–ICDP Expedition 364 recovered drill core samples at borehole M0077A from the peak ring of the Chicxulub impact crater, offshore of the Yucatán peninsula in the Gulf of México, have been studied comprehensively. In the lowermost ~600 m of the drill core, impact–deformed granitoids, and minor felsite and dolerite dykes are intercalated with impact melts and breccias. Zircon U-Pb dating of granitoids yielded ages of around 326 ± 5 Ma, representing the first recovery of Late Paleozoic magmatic rocks from the Maya block, which could be genetically related to the convergence of Laurentia and Gondwana. The granitoids show the features of high K2O/Na2O, LaN/YbN and Sr/Y ratios, but very low Yb and Y contents, indicating an adakitic affinity. They are also characterized by slightly positive ԑNd(326Ma) of 0.17–0.68, intermediate initial 87Sr/86Sr(326Ma) of 0.7036–0.7047 and two–stage Nd model age (TDM2) of 1027–1069 Ma, which may indicate a less evolved crustal source. Thus, the adakitic granitoids were probably generated by partial melting of thickened crust, with source components similar to Neoproterozoic metagabbro in the Carolina block (Pan–African Orogeny materials) along Peri–Gondwana. Felsite dykes are shoshonitic with typical continental arc features that are sourced from a metasomatic mantle wedge by slab–fluids. Dolerite dykes display OIB–type features such as positive Nb and Ta anomalies and low ThNpm/NbNpm. In our interpretation, the Chicxulub adakitic granitoids of this study are formed by crustal anatexis due to asthenospheric upwelling resulting from slab breakoff. Through comparing sources and processes of Late Paleozoic magmatism along the Peri–Gondwanan realm, a tearing slab breakoff model may explain the discontinuous magmatism that appears to have occurred during the convergence of Laurentia and Gondwana.
Published: 2020

16. Visualizing the invisible: class excursions to ignite children’s enthusiasm for microbes

Author: Esther Garcia Cela, Seth R. Bordenstein, Sharon Sivinski, Max M. Häggblom, Saskia Bindschedler, Pilar Junier, Fengping Wang, Rup Lal, Bonnie K. Baxter, Charles S. Cockell, Brajesh K. Singh, John E. Hallsworth, Nicole S. Webster, Terry J. McGenity, Carol Verheecke-Vaessen, Olga C. Nunes, Nancy P. Keller, Eddy J. Smid, Lisa Y. Stein, Paola Scavone, Corinne Whitby, Lone Gram, Amare Gessesse, Cindy Morris, Max Chavarría, Søren Molin, Cédric Lood, Kenneth N. Timmis, Antoine Danchin, André Antunes, Shuang Jiang Liu, University of Essex, Botswana International University of Science & Technology (BIUST), Queen's University [Belfast] (QUB), University of Hertfordshire [Hatfield] (UH), Cranfield University, Shanghai Jiao Tong University [Shanghai], Universidad de Costa Rica (UCR), Centro Nacional de Innovaciones Biotecnologicas (Cenibiot), National Center of High Technology (CeNAT-CONARE), Rutgers University [Newark], Rutgers University System (Rutgers), Technical University of Denmark [Lyngby] (DTU), Institut Cochin (IC UM3 (UMR 8104 / U1016)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Wageningen University and Research [Wageningen] (WUR), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, Chinese Academy of Sciences [Beijing] (CAS), University of Wisconsin-Madison, University of Alberta, Vanderbilt University [Nashville], The Energy and Resources Institute (TERI), Universidade do Porto, Western Sydney University, Australian Institute of Marine Science (AIMS), University of Queensland [Brisbane], Unité de Pathologie Végétale (PV), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institute of Biology of the University of Neuchâtel, Université de Neuchâtel (UNINE), Macau University of Science and Technology (MUST), Westminster College, Instituto de Investigaciones Biológicas Clemente Estable [Montevideo] (IIBCE), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Science and Technology Facilities Council. Grant Number: ST/S001425/1, Natural Environment Research Council. Grant Number: NE/S005560/1, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Universidade do Porto = University of Porto, and DECOGNET, VERONIQUE
Subjects: Adult, Value (ethics), media_common.quotation_subject, [SHS.EDU]Humanities and Social Sciences/Education, [SHS.EDU] Humanities and Social Sciences/Education, education, Bioengineering, Applied Microbiology and Biotechnology, Biochemistry, Levensmiddelenmicrobiologie, Literacy, 03 medical and health sciences, SDG 3 - Good Health and Well-being, Humans, Prealbumin, Life Science, Sociology, microbiologie, Child, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, Children, Curriculum, VLAG, 030304 developmental biology, media_common, sensibilisation, Benzoxazoles, 0303 health sciences, Enthusiasm, Class excursions, 030306 microbiology, business.industry, Flexibility (personality), Amyloidosis, Public relations, Outreach, Microbes, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Action (philosophy), Preparedness, Food Microbiology, business, TP248.13-248.65, Biotechnology
Abstract: We have recently argued that, because microbes have pervasive – often vital – influences on our lives, and that therefore their roles must be taken into account in many of the decisions we face, society must become microbiology‐literate, through the introduction of relevant microbiology topics in school curricula (Timmis et al. 2019. Environ Microbiol 21: 1513‐1528). The current coronavirus pandemic is a stark example of why microbiology literacy is such a crucial enabler of informed policy decisions, particularly those involving preparedness of public‐health systems for disease outbreaks and pandemics. However, a significant barrier to attaining widespread appreciation of microbial contributions to our well‐being and that of the planet is the fact that microbes are seldom visible: most people are only peripherally aware of them, except when they fall ill with an infection. And it is disease, rather than all of the positive activities mediated by microbes, that colours public perception of ‘germs’ and endows them with their poor image. It is imperative to render microbes visible, to give them life and form for children (and adults), and to counter prevalent misconceptions, through exposure to imagination‐capturing images of microbes and examples of their beneficial outputs, accompanied by a balanced narrative. This will engender automatic mental associations between everyday information inputs, as well as visual, olfactory and tactile experiences, on the one hand, and the responsible microbes/microbial communities, on the other hand. Such associations, in turn, will promote awareness of microbes and of the many positive and vital consequences of their actions, and facilitate and encourage incorporation of such consequences into relevant decision‐making processes. While teaching microbiology topics in primary and secondary school is key to this objective, a strategic programme to expose children directly and personally to natural and managed microbial processes, and the results of their actions, through carefully planned class excursions to local venues, can be instrumental in bringing microbes to life for children and, collaterally, their families. In order to encourage the embedding of microbiology‐centric class excursions in current curricula, we suggest and illustrate here some possibilities relating to the topics of food (a favourite pre‐occupation of most children), agriculture (together with horticulture and aquaculture), health and medicine, the environment and biotechnology. And, although not all of the microbially relevant infrastructure will be within reach of schools, there is usually access to a market, local food store, wastewater treatment plant, farm, surface water body, etc., all of which can provide opportunities to explore microbiology in action. If children sometimes consider the present to be mundane, even boring, they are usually excited with both the past and the future so, where possible, visits to local museums (the past) and research institutions advancing knowledge frontiers (the future) are strongly recommended, as is a tapping into the natural enthusiasm of local researchers to leverage the educational value of excursions and virtual excursions. Children are also fascinated by the unknown, so, paradoxically, the invisibility of microbes makes them especially fascinating objects for visualization and exploration. In outlining some of the options for microbiology excursions, providing suggestions for discussion topics and considering their educational value, we strive to extend the vistas of current class excursions and to: (i) inspire teachers and school managers to incorporate more microbiology excursions into curricula; (ii) encourage microbiologists to support school excursions and generally get involved in bringing microbes to life for children; (iii) urge leaders of organizations (biopharma, food industries, universities, etc.) to give school outreach activities a more prominent place in their mission portfolios, and (iv) convey to policymakers the benefits of providing schools with funds, materials and flexibility for educational endeavours beyond the classroom UK Research and Innovation/[ST/S001425/1]/UKRI/Reino Unido Functionality of Urban Soils/[NE/S005560/1]/FUSED/Reino Unido UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA)
Published: 2020
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17. Dayside nitrogen and carbon escape on Titan: the role of exothermic chemistry

Author: F. He, Jun Cui, D.-D. Niu, Panayotis Lavvas, Yong Wei, H. Gu, XiaoShu Wu, J. H. Guo, Macau University of Science and Technology (MUST), National Astronomical Observatories [Beijing] (NAOC), Chinese Academy of Sciences [Beijing] (CAS), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Yunnan Astronomical Observatory, Institute of Geology and Geophysics [Beijing] (IGG), Space Science Institute [Macau] (SSI), School of Atmospheric Sciences [Zhuhai], and Sun Yat-Sen University [Guangzhou] (SYSU)
Subjects: Exothermic reaction, 010504 meteorology & atmospheric sciences, Atmospheric escape, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Chemistry, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Chemical reaction, symbols.namesake, 13. Climate action, Space and Planetary Science, Chemical physics, [SDU]Sciences of the Universe [physics], 0103 physical sciences, symbols, Terrestrial planet, [CHIM]Chemical Sciences, Test particle, Ionosphere, Titan (rocket family), 010303 astronomy & astrophysics, Dissociative recombination, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Context. Atmospheric escape has an appreciable impact on the long-term climate evolution on terrestrial planets. Exothermic chemistry serves as an important mechanism driving atmospheric escape and the role of such a mechanism is of great interest for Titan due to its extremely complicated atmospheric and ionospheric composition. Aims. This study is devoted to a detailed investigation of neutral N and C escape on the dayside of Titan, which is driven by exothermic neutral–neutral, ion–neutral, and dissociative recombination (DR) reactions. It was carried out based on the extensive measurements of Titan’s upper atmospheric structure by a number of instruments on board Cassini, along with an improved understanding of the chemical network involved. Methods. A total number of 14 C- and N-containing species are investigated based on 146 exothermic chemical reactions that release hot neutrals with nascent energies above their respective local escape energies. For each species and each chemical channel, the hot neutral production rate profile is calculated, which provides an estimate of the corresponding escape rate when combined with the appropriate escape probability profile obtained from a test particle Monte Carlo model. Results. Our calculations suggest a total N escape rate of 9.0 × 1023 s−1 and a total C escape rate of 4.2 × 1023 s−1, driven by exothermic chemistry and appropriate for the dayside of Titan. The former is primarily contributed by neutral-neutral reactions, whereas the latter is dominated by ion–neutral reactions; however, contributions from neutral–neutral and DR reactions to the latter cannot be ignored either. Our calculations further reveal that the bulk of N escape is driven by hot N(4S) production from the collisional quenching of N(2D) by ambient N2, while C escape is mainly driven by hot CH3 and CH4 production via a number of important ion–neutral and neutral–neutral reactions. Conclusions. Considered in the context of prior investigations of other known escape mechanisms, we suggest that exothermic chemistry is likely to contribute appreciably to non-thermal C escape on the dayside of Titan, although it plays an insignificant role in N escape.
Published: 2020

18. Long-term monitoring of comet 67P/Churyumov–Gerasimenko’s jets with OSIRIS onboard Rosetta

Author: Holger Sierks, Ekkehard Kührt, Philippe Lamy, L. M. Lara, Marco Fulle, M. De Cecco, Monica Lazzarin, H. U. Keller, A. Gicquel, M. I. Schmitt, Dennis Bodewits, Xian Shi, Jessica Agarwal, J. J. López-Moreno, Imre Toth, M. F. A'Hearn, Stefano Mottola, Olivier Groussin, Sonia Fornasier, R. Rodrigo, J. L. Bertaux, Frank Scholten, Cesare Barbieri, D. Prasanna, Jörg Knollenberg, Stefano Debei, Jakob Deller, Wing-Huen Ip, Stubbe F. Hviid, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, Nilda Oklay, Ivano Bertini, Michael Küppers, Detlef Koschny, Nicolas Thomas, G. Cremonese, Francesco Marzari, J.-B. Vincent, V. Da Deppo, Mohamed Ramy El-Maarry, Marc Hofmann, Maurizio Pajola, Hans Rickman, J.-R. Kramm, P. J. Gutierrez, M. A. Barucci, Giampiero Naletto, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Epoch (astronomy), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Equinox, 01 natural sciences, Latitude, 0103 physical sciences, comets, Comets: individual: 67P/Churyumov, Gerasimenko, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Jet (fluid), biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, 620 Engineering, biology.organism_classification, 13. Climate action, Space and Planetary Science, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We used the OSIRIS camera system onboard the Rosetta spacecraft to monitor jet activity of comet 67P/Churyumov-Gerasimenko. With a monthly cadence, we covered an epoch from December 2014 to October 2015, thereby including the first equinox and the perihelion passage. Jet features were measured in individual images, which were used to perform a statistical inversion. The study provides maps for the locations of likeliest sources of jet activity on the comet’s surface as a function of time. The sources follow the sub-solar latitude, show clustering and a broadening of the activity band with time in the Northern hemisphere. On the Southern hemisphere they are not clustered but show a broader spread over all longitudes which is either related to the north-south dichotomy of the comet’s topography or due to a higher insolation during southern summer.
Published: 2017

19. Spectrophotometric variegation of the layering in comet 67P/Churyumov-Gerasimenko as seen by OSIRIS

Author: Cesare Barbieri, W-H. Ip, Pedro J. Gutiérrez, Jakob Deller, Björn Davidsson, D. Bodewits, Gloria Tognon, R. Rodrigo, F. La Forgia, V. Petropoulou, Philippe Lamy, Prasanna Deshapriya, H. U. Keller, Cecilia Tubiana, M. A. Barucci, Holger Sierks, V. Da Deppo, Carsten Güttler, Matteo Massironi, Marco Fulle, Imre Toth, Michel Franceschi, Sabrina Ferrari, Giampiero Naletto, Alice Lucchetti, Detlef Koschny, M. De Cecco, E. Frattin, Sonia Fornasier, J. J. Lopez-Moreno, Monica Lazzarin, Maurizio Pajola, Ivano Bertini, Luca Penasa, Luisa Lara, Francesca Ferri, Francesco Marzari, Pamela Cambianica, Jean-Loup Bertaux, Gabriele Cremonese, Stefano Debei, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics [Auburn], Auburn University (AU), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), NASA-California Institute of Technology (CALTECH), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Technische Universität Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Tognon, Gloria, Ferrari, S., Penasa, L., La Forgia, F., Massironi, M., Naletto, G., Lazzarin, M., Cambianica, P., Lucchetti, A., Pajola, M., Ferri, F., Güttler, C., Davidsson, B., Deshapriya, P., Fornasier, S., Mottola, S., Tóth, I., Sierks, H., Lamy, P. L., Rodrigo, R., Koschny, D., Barbieri, C., Barucci, M. A., Bertaux, J. -L., Bertini, I., Bodewits, D., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Deller, J., Franceschi, M., Frattin, E., Fulle, M., Gutiérrez, P. J., Ip, W. -H., Keller, H. U., Lara, L. M., López-Moreno, J. J., Marzari, F., Petropoulou, V., Shi, X., and Tubiana, C.
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Outcrop, Multispectral image, Narrow angle, Astrophysics, 01 natural sciences, WATER ICE, NUCLEUS, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, data analysis [methods], medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Physics, Multispectral data, biology, general [Comets], Astronomy and Astrophysics, biology.organism_classification, Lobe, Comets: general, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis, Osiris, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Between August 2014 and September 2016, the ESA space mission Rosetta escorted comet 67P/Churyumov-Gerasimenko (67P) during its perihelion passage. The onboard OSIRIS Narrow Angle Camera (NAC) acquired high-resolution multispectral images of the cometary surface. These datasets allowed a characterization of the spectrophotometric variegation of the layering of the large lobe, correlated with the layer structural elevation. Aims. We perform a spectrophotometric characterization of the outcropping stratification of the small lobe of 67P as a function of its structural elevation, and consequently, a spectrophotometric comparison of the layered outcrops of the two lobes. Methods. We selected two sequences of post-perihelion OSIRIS NAC images (similar to 2.4 au outbound to the Sun), from which we built up two multispectral images, framing an extended geological section of the onion-like stratification of the small lobe. Then we classified the consolidated areas of the outcropping and the relative coarse deposits that were identified in the multispectral data with a two-class maximum likelihood method. For this, we defined the classes as a function of the structural elevation of the surface. Results. As a result, we identified a brightness variegation of the surface reflectance that is correlated with the structural elevation. The outer class, which is located at higher elevations, appears darker than the inner class. This fits previously obtained results for the large lobe. The reflectance values of the nucleus of 67P tend to decrease with increasing structural elevation. Conclusions. The observed spectrophotometric variegation can be due to a different texture as well as to a different content of volatiles and refractories. We suggest that the outer outcrops appear darker because they have been exposed longer, and the inner outcrops appear brighter because the surface has been more effectively rejuvenated. We interpret this variegation as the result of an evolutionary process.© ESO 2019, We are grateful to Andrea Longobardo for suggestions and corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS - University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2019

20. Multidisciplinary analysis of the Hapi region located on Comet 67P/Churyumov–Gerasimenko

Author: Wing-Huen Ip, Philippe Lamy, Carsten Güttler, F. La Forgia, Nilda Oklay, R. Rodrigo, Z. Y. Lin, Dennis Bodewits, Stefano Debei, V. Da Deppo, H. U. Keller, Luca Penasa, Jakob Deller, Maurizio Pajola, Alice Lucchetti, Gabriele Cremonese, Giampiero Naletto, Sonia Fornasier, Detlef Koschny, Marco Fulle, P. J. Gutierrez, M. De Cecco, Holger Sierks, J. J. Lopez Moreno, Francesco Marzari, J.-C. Lee, Matteo Massironi, F. Preusker, Ivano Bertini, Stubbe F. Hviid, Sabrina Ferrari, Imre Tóth, Jessica Agarwal, Pamela Cambianica, Xian Shi, Frank Scholten, Lorenza Giacomini, Jean-Loup Bertaux, M. A. Barucci, Stefano Mottola, Luisa Lara, Björn Davidsson, M. R. El Maarry, Clement Feller, Cecilia Tubiana, Monica Lazzarin, Jean-Baptiste Vincent, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Geoscienze [Padova], Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Department of Physics [Auburn], Auburn University (AU), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], INAF - Osservatorio Astronomico di Trieste (OAT), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université Libre de Bruxelles [Bruxelles] (ULB), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), European Space Agency, Swedish National Space Board, Ministerio de Educación y Ciencia (España), Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, German Centre for Air and Space Travel, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Pajola, M. [0000-0002-3144-1277], Penasa, L. [0000-0002-6394-3108], Fornasier, S. [0000-0001-7678-3310], Lucchetti, A. [0000-0001-7413-3058], Vicent, J. B. [0000-0001-6575-3079], Naletto, G. [0000-0003-2007-3138], Barucci, M. A. [0000-0002-1345-0890], Bertaux, J. L. [0000-0003-0333-229X], Deller, J. [0000-0001-8341-007X], Fulle, M. [0000-0001-8435-5287], Güttler, C. [0000-0003-4277-1738], Tubiana, C. [0000-0001-8475-9898], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH)-NASA, PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Université libre de Bruxelles (ULB), Agenzia Spaziale Italiana (ASI), Swedish National Space Agency (SNSA), Deutsches Zentrum für Luft- und Raumfahrt (DLR), and Centre National D'Etudes Spatiales (CNES)
Subjects: Asteroiden und Kometen, statistical [Methods], Comet, individual (67P C-G) [Comets], Comets: individual (67P C-G), Methods: data analysis, Methods: statistical, 01 natural sciences, Methods statistical, Gravitational potential, 0103 physical sciences, data analysis [Methods], 010303 astronomy & astrophysics, Southern Hemisphere, Physics, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Multidisciplinary analysis, Planetengeodäsie, 67P/Churyumov–Gerasimenko Comets Rosetta Hapi, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, methods: data analysis –methods: statistical – comets: individual (67P C-G), Space and Planetary Science, Ridge, individual: 67P C-G [Comets], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: By using the Rosetta/OSIRIS-NAC data set taken in 2014 August, we focus on the neck region, called Hapi, located on 67P Churyumov-Gerasimenko's Northern hemisphere. The gravitational potential and slopes of Hapi, coupled with the geological unit identification and the boulder size-frequency distributions, support the interpretation that both taluses and gravitational accumulation deposits observable on Hapi are the result of multiple cliff collapses that occurred at different times. By contrast, the fine-particle deposits observable in the central part of the study area are made of aggregates coming from the Southern hemisphere and deposited during each perihelion passage. Both the consolidated terrains on the western part of Hapi, as well as the centrally aligned ridge made of boulder-like features, suggest that Hapi is in structural continuity with the onion-like structure of the main lobe of 67P. Despite the dusty blanket observable on Hapi, its terrains are characterized by water-ice-rich components that, once repeatedly and rapidly illuminated, sublimate, hence resulting in the strong jet activity observed in 2014 August.© 2019 The Author(s)., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2019

21. Pronounced morphological changes in a southern active zone on comet 67P/Churyumov-Gerasimenko

Author: Pedro Hasselmann, Giampiero Naletto, Carsten Güttler, Horst Uwe Keller, Detlef Koschny, Philippe Lamy, J. M. Sunshine, J. D. P. Deshapriya, L. M. Lara, Francesco Marzari, M. De Cecco, S. Fornasier, R. Rodrigo, Holger Sierks, V. Da Deppo, Monica Lazzarin, G. Cremonese, Marco Fulle, Ivano Bertini, Björn Davidsson, Dennis Bodewits, P. J. Gutierrez, Cecilia Tubiana, Stefano Debei, Van H. Hoang, Xian Shi, M. A. Barucci, W-H. Ip, Clement Feller, J.-L. Bertaux, Dominique Bockelée-Morvan, J. J. Lopez-Moreno, Jakob Deller, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Physics [Hanoi], Vietnam Academy of Science and Technology (VAST), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Planetary Science Institute [Tucson] (PSI), University of Trento [Trento], ANR-17-CE31-0004,CLASSY,Composition des surfaces du Système Solaire de bas albédo(2017), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA)-European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and California Institute of Technology (CALTECH)-NASA
Subjects: 67P/Churyumov-Gerasimenko - methods, 010504 meteorology & atmospheric sciences, Comet, Individual, Astrophysics, Fault scarp, 01 natural sciences, Indirect evidence, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, High spatial resolution, Comets, Active zone, miscellaneous [methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Miscellaneous, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Geodesy, 13. Climate action, Space and Planetary Science, methods: miscellaneous, Falling (sensation), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Production rate
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., A smooth deposit in the southern Khonsu region has been seen in ESA/Rosetta observations as active during the second half of 2015, when the southern summer coincided with the perihelion passage of 67P/Churyumov-Gerasimenko (67P). Image color sequences acquired by the OSIRIS instrument in the period of January 2015 to July 2016, pre- and post-perihelion, show the occurrence of several small transient events as well as three massive outbursts (-10 to 1500 tons). High spatial resolution images taken one year and a half apart allowed us to track a variety of sources: the formation of cavities that are 1.3-14 m deep, ice-enriched patches, scarp retraction, and a second 50 m-wide boulder. We then estimated their masses and the dust mass of their corresponding plumes and outbursts. In particular, the deformation left by that boulder and its lack of talus may provide evidence for the lifting and subsequent falling back to the surface of large blocks. We calculate that a minimum vapor production rate of 1.4 x 10(24) m(-2) s(-1) is required to lift such an object. The comparison of the masses that are lost in the new cavities to the dust mass of outbursts gives indirect evidence of highly volatile ice pockets underneath. The spectrophotometric analysis and boulder counting also provides evidence for cavities that formed only 30 m apart with different spectral slopes, two long-standing ice patches, and local variations in the boulder-size frequency distribution. All this points to sub-surface ice pockets with different degrees of depth. Finally, the total mass of the morphological changes compared to most recent calculations of the total released mass by activity on 67P is estimated to be between 1.5 and 4.2%. This means that as many as about 25 similar active zones across the nucleus would be enough to sustain the entire cometary activity.© P. H. Hasselmann et al. 2019, P.H.H. would like to thank Alice Bernard for her support. This work was funded by the DIM-ACAV project (Ile-de-France). OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We acknowledge the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004).
Published: 2019

22. Thickness of Lunar Mare Basalts: New Results Based on Modeling the Degradation of Partially Buried Craters

Author: Wenzhe Fa, Meng-Hua Zhu, Jun Du, Minggang Xie, Mark A. Wieczorek, Yuzhen Cai, Peking University [Beijing], Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Macau University of Science and Technology (MUST), Center for Excellence in Comparative Planetology, and Chinese Academy of Sciences [Beijing] (CAS)
Subjects: Basalt, 010504 meteorology & atmospheric sciences, Lunar mare, Geochemistry, 01 natural sciences, Geophysics, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Impact crater, Space and Planetary Science, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Degradation (geology), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Partially buried craters on the Moon are those craters whose distal ejecta are covered by lava flows and where the crater rim crest still protrudes above the mare plain. Based on the difference in rim heights between a partially buried crater and an unburied crater, previous studies estimated the thicknesses of the lunar mare basalts. However, these studies did not consider the erosion of the crater rim height, which can result in an overestimate in the derived thickness. By using recent high-resolution topographic data, we report a basalt thickness estimation method based on numerically modeling the topographic degradation of partially buried craters. We identified 661 buried craters over the lunar surface, and their spatial distribution suggests a preferential occurrence along the mare-highland boundaries. An elevation model of fresh lunar craters was derived, and the topographic diffusion equation was used to model crater degradation. By modeling the formation, degradation, and flooding of partially buried craters, basalt thicknesses were estimated for 41 mare craters whose rims are completely exposed. The resulting mare basalt thicknesses vary from 33 to 455 m, with a median value of 105 m that is 95 m smaller than that derived when not considering crater degradation. The estimated eruption rate of lunar mare basalts is found to have peaked at 3.4 Ga and then decreased with time, indicating a progressive cooling of the lunar interior. As a by-product from the crater degradation model, our results suggest that the topographic diffusivity of lunar craters increases with diameter. Plain Language Summary The thickness of mare basalts that partially cover a lunar crater can be estimated from the crater shape. To simplify this problem, previous studies used the shape of a fresh lunar crater, which had been well-characterized beforehand. In reality, however, the lunar crater degrades with time, which results in a more complicated, time-dependent crater shape. In this study, a crater degradation model is used to better estimate mare basalt thicknesses. Our results show that the mare basalt thickness could be overestimated by a factor of two when crater degradation is not considered. Our results constrain the volcanic eruption rate with time and imply that the crater degradation rate scales with crater size.
Published: 2019

23. The backscattering ratio of comet 67P/Churyumov-Gerasimenko dust coma as seen by OSIRIS onboard Rosetta

Author: Pamela Cambianica, F. La Forgia, Jean-Loup Bertaux, P. J. Gutierrez, Alice Lucchetti, E. Frattin, Alessandra Rotundi, Detlef Koschny, Pedro Hasselmann, Xian Shi, Wing-Huen Ip, Giovanna Rinaldi, Philippe Lamy, Carsten Güttler, Giampiero Naletto, Stefano Mottola, Monica Lazzarin, Marco Fulle, J. J. Lopez Moreno, Sabrina Ferrari, Nafiseh Masoumzadeh, M. A. Barucci, H. U. Keller, D. Guirado, Imre Toth, V. Petropoulou, Gábor L. Kovács, Holger Sierks, Gabriele Cremonese, M. De Cecco, Cesare Barbieri, L. M. Lara, Björn Davidsson, Jakob Deller, Dennis Bodewits, S. Ivanovsky, Francesca Ferri, Cecilia Tubiana, Luca Penasa, Jessica Agarwal, Stefano Debei, Ivano Bertini, Maurizio Pajola, Olga Muñoz, Francesco Marzari, S. Fornasier, Matteo Massironi, F. Moreno, R. Rodrigo, V. Da Deppo, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Ministerio de Educación y Ciencia (España), Swedish National Space Agency, European Space Agency, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astronomico di Padova (OAPD), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Physics [Auburn], Auburn University (AU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], Fulle, M. [0000-0001-8435-5287], Tubiana, C. [0000-0001-8475-9898], Güttler, C. [0000-0003-4277-1738], Pajola, M. [0000-0002-3144-1277], Rinaldi, G. [0000-0002-2968-0455], Naletto, G. [0000-0003-2007-3138], Barucci, M. A. [0000-0002-1345-0890], Bertaux, J. L. [0000-0003-0333-229X], Deller, J. [0000-0001-8341-007X], Fornasier, S. [0000-0001-7678-3310], Penasa, L. [0000-0002-6394-3108], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), and Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Subjects: 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, photometry, Comet, data analysis, scattering –methods: data analysis – techniques: image processing – techniques: photometric – comets: individual: 67P/Churyumov-Gerasimenko, techniques: image processing, Astrophysics, 01 natural sciences, Photometry (optics), Scattering, techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Churyumov–Gerasimenko, image processing [Techniques], data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], scattering, methods: data analysis, techniques: image processing, techniques: photometric, comets: individual: 67P/Churyumov-Gerasimenko, Phase angle, scattering, photometric [Techniques], comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, biology.organism_classification, methods: data analysis, image processing, 13. Climate action, Space and Planetary Science, Drag, Temporal resolution, Inverse scattering problem, Osiris, individual: 67P [Comets], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Remote sensing observations of dust particles ejected from comets provide important hints on the intimate nature of the materials composing these primitive objects. The measurement of dust coma backscattering ratio, BSR, defined as the ratio of the reflectance at phase angle 0 ◦ and 30 ◦ , helps tuning theoretical models aimed at solving the inverse scattering problem deriving information on the nature of the ejected particles. The Rosetta/OSIRIS camera sampled the coma phase function of comet 67P, with four series acquired at low phase angles from 2015 January to 2016 May. We also added previously published data to our analysis to increase the temporal resolution of our findings. We measured a BSR in the range ∼ [1.7-3.6], broader than the range found in literature from ground-based observations of other comets. We found that during the post-perihelion phase, the BSR is systematically larger than the classical cometary dust values only for nucleocentric distances smaller than ∼ 100 km. We explain this trend in terms of a cloud of chunks orbiting the nucleus at distances < 100 km ejected during perihelion and slowly collapsing on the nucleus over a few months because of the coma gas drag. This also implies that the threshold particle size for the dust phase function to become similar to the nucleus phase function is between 2.5 mm and 0.1 m, taking into account previous Rosetta findings. © 2018 The Author(s)., The support of the national funding agencies of Germany (DLR: Deutschen Zentrums fur Luft-und Raumfahrt), France (CNES: Centre national d' etudes spatiales), Italy (ASI: Agenzia Spaziale Italiana), Spain (MEC: Ministry of Education& Science), Sweden (SNSB: Swedish National Space Board), and the European Space Agency (ESA) Technical Directorate is gratefully acknowledged.
Published: 2019

24. Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta

Author: D. Bodewits, Lyn R. Doose, Giovanna Rinaldi, U. Fink, M. De Cecco, Ivano Bertini, Marco Fulle, Maria Teresa Capria, Anny Chantal Levasseur-Regourd, D. Bockelée-Morvan, Imre Toth, Luisa Lara, Sonia Fornasier, H. Krueger, Mauro Ciarniello, Vladimir E. Zakharov, Holger Sierks, Alessandra Migliorini, Gabriele Arnold, Andrea Longobardo, Carsten Güttler, X. Hu, Michelangelo Formisano, Francesco Marzari, Xian Shi, Wing-Huen Ip, Philippe Lamy, F. La Forgia, Stefano Mottola, Gabriele Cremonese, Detlef Koschny, Zhong-Yi Lin, David Kappel, Raphael Marschall, Fredric W. Taylor, V. Da Deppo, S. Ivanovski, J. J. López-Moreno, Fabrizio Capaccioni, Gianrico Filacchione, H. U. Keller, Stéphane Erard, M. C. De Sanctis, Jean-Loup Bertaux, J. Deller, Pedro J. Gutiérrez, Stefano Debei, R. Rodrigo, Jacques Crovisier, Giampiero Naletto, Björn Davidsson, Cecilia Tubiana, M. A. Barucci, Colin Snodgrass, Monica Lazzarin, Ludmilla Kolokolova, Agenzia Spaziale Italiana, German Research Foundation, Centre National de la Recherche Scientifique (France), Ministerio de Economía y Competitividad (España), Government of Sweden, European Space Agency, l'Observatoire de Paris, Science and Technology Facilities Council (UK), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin (TU), International Space Science Institute [Bern] (ISSI), INAF - Osservatorio Astronomico di Trieste (OAT), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Physik und Astrophysik [Potsdam], Universität Potsdam, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Universita degli studi di Napoli 'Parthenope' [Napoli], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Oxford], University of Oxford [Oxford], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Technische Universität Berlin (TUB), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Comet, Comets, Data analysis, General, Individual, Methods, FOS: Physical sciences, Coma (optics), Spatial distribution, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Methods: data analysis, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, data analysis [methods], ddc:530, 010303 astronomy & astrophysics, Southern Hemisphere, Comet: individual: 67P/Churyumov-Gerasimenko, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Diurnal temperature variation, Leitungsbereich PF, comets: individual: 67P/Churyumov-Gerasimenko, Institut für Physik und Astronomie, general [Comets], Astronomy and Astrophysics, Comets: general, 13. Climate action, Space and Planetary Science, astro-ph.EP, Environmental science, Spatial variability, Longitude, Astrophysics - Earth and Planetary Astrophysics
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet.© C. Tubiana et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Daten-technik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. VIRTIS was built by a consortium, which includes Italy, France, and Germany, under the scientific responsibility of the Istituto di Astrofisica e Planetologia Spaziali of INAF, Italy, which also guides the scientific operations. The VIRTIS instrument development, led by the prime contractor Leonardo-Finmeccanica (Florence, Italy), has been funded and managed by ASI, with contributions from Observatoire de Meudon financed by CNES, and from DLR. We thank the Rosetta Science Ground Segment and the Rosetta Mission Operations Centre for their support throughout all the phases of the mission. The VIRTIS calibrated data will be available through the ESA's Planetary Science Archive Website (www.rssd.esa.int) and is available upon request until posted to the archive. We thank the following institutions and agencies for support of this work: Italian Space Agency (ASI, Italy) contract number I/024/12/1, Centre National d'Etudes Spatiales (CNES, France), DLR (Germany), NASA (USA) Rosetta Program, and Science and Technology Facilities Council (UK).
Published: 2019

25. Quantitative analysis of isolated boulder fields on comet 67P/Churyumov-Gerasimenko

Author: Philippe Lamy, G. Cremonese, W.-H. Ip, Pamela Cambianica, Marco Fulle, Sabrina Ferrari, Dennis Bodewits, Matteo Massironi, Alice Lucchetti, Frank Scholten, Jean-Loup Bertaux, P. J. Gutierrez, F. La Forgia, Björn Davidsson, Francesco Marzari, Carsten Güttler, Z. Y. Lin, Jakob Deller, Cecilia Tubiana, Ivano Bertini, Detlef Koschny, M. De Cecco, Monica Lazzarin, M. A. Barucci, Holger Sierks, Emanuele Simioni, H. U. Keller, S. Fornasier, R. Rodrigo, Stefano Debei, L. M. Lara, V. Da Deppo, Xian Shi, Stefano Mottola, J.-B. Vincent, Giampiero Naletto, Luca Penasa, Maurizio Pajola, Imre Tóth, J. J. Lopez-Moreno, Cambianica, P. [https://orcid.org/0000-0002-8091-4915], European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Agencia Estatal de Investigación (AEI), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Agenzia Spaziale Italiana (ASI), Swedish National Space Agency (SNSA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Geoscienze [Padova], Department of Physics [Auburn], Auburn University (AU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets, Data analysis, General, Individual, Methods, Population, Comet, Narrow angle, Geometry, Astrophysics, 01 natural sciences, Power law, Fractal, individual: 67P/Churyumov-Gerasimenko [Comets], Power index, 0103 physical sciences, education, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Comets: individual: 67P/Churyumov-Gerasimenko, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Astronomy and Astrophysics, methods: data analysis, Comets: general, Space and Planetary Science, Spatial ecology, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We provide a detailed quantitative analysis of isolated boulder fields situated in three different regions of comet 67P/Churyumov-Gerasimenko: Imhotep, Hapi, and Hatmehit. This is done to supply a useful method for analyzing the morphology of the boulders and to characterize the regions themselves. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale smaller than 2 mpx(-1) and analyzed the size-frequency distribution and the cumulative fractional area per boulder population. In addition, we correlated shape parameters, such as circularity and solidity, with both the spatial and the size-frequency distribution of the three populations. Results. We identified 11 811 boulders in the Imhotep, Hapi, and Hatmehit regions. We found that the Hatmehit and Imhotep areas show power indices in the range of -2.3/-2.7. These values could represent a transition between gravitational events caused by thermal weathering and sublimation, and material formed during collapses that has undergone sublimation. The Hapi area is characterized by a lower power index (-1.2/-1.7), suggesting that those boulders have a different origin. They can be the result of material formed during gravitational events and collapses that has undergone continuous fragmentation. We calculated the cumulative fractional area (CFA) in order to investigate how the area is covered by boulders as a function of their sizes. The Hatmehit and Imhotep regions show a CFA that is well fit by a power law. In contrast, the Hapi area does not show the same trend. We analyzed the fractal distributions, finding that the populations seem to be fractal at all dimensions, except for the Hapi distribution, which shows a possible fractal behavior for small dimensions only. Finally, the average values of the shape parameters reveal solid and roundish boulders in all populations we studied.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck Institut fur Sonnensystemforschung, in Guttingen, Germany, CISAS University of Padova, Italy, the Laboratoire de Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. We made use of Arcgis 10.3.1 software together with the Matlab, Java, and ImageJ software to perform our analysis. I thank Frederic Moisy for sharing the box-count work.
Published: 2019

26. Rosetta/OSIRIS observations of the 67P nucleus during the April 2016 flyby: High-resolution spectrophotometry

Author: H. U. Keller, Alice Lucchetti, M. De Cecco, Giampiero Naletto, D. Bodewits, Monica Lazzarin, Francesco Marzari, R. Rodrigo, P. J. Gutiérrez, Maurizio Pajola, Sonia Fornasier, J. D. P. Deshapriya, Stefano Debei, F. La Forgia, A. Barucci, J. J. López-Moreno, V. Da Deppo, Frank Preusker, Wing-Huen Ip, Philippe Lamy, Matteo Massironi, C. Feller, Holger Sierks, Pedro Hasselmann, Gabriele Cremonese, Björn Davidsson, Cecilia Tubiana, Luisa Lara, B. Gaskell, Carsten Güttler, Frank Scholten, Ivano Bertini, Marco Fulle, Sabrina Ferrari, Xian Shi, Stefano Mottola, Jean-Loup Bertaux, Detlef Koschny, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Planetary Science Institute [Tucson] (PSI), Feller, C. [0000-0002-2941-3875], Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, techniques: image processing, Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Frost line, Spectrophotometry, Spectral slope, Methods, Churyumov–Gerasimenko, image processing [Techniques], space vehicles: instruments, data analysis [Methods], 010303 astronomy & astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Physics, [PHYS]Physics [physics], biology, medicine.diagnostic_test, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Resolution (electron density), Comets, Data analysis, Image processing, Individual, Instruments, Space vehicles, Techniques, individual: 67P [Comets], Comet, FOS: Physical sciences, Terrain, Context (language use), instruments [Space vehicles], 0103 physical sciences, medicine, 0105 earth and related environmental sciences, Planetengeodäsie, space vehicles – space vehicles: instruments – comets: individual: 67P/Churyumov–Gerasimenko – techniques: image processing – methods: data analysis, Astronomy and Astrophysics, biology.organism_classification, methods: data analysis, 13. Climate action, Space and Planetary Science, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: From August 2014 to September 2016, the Rosetta spacecraft followed comet 67P/Churyumov-Gerasimenko along its orbit. After the comet passed perihelion, Rosetta performed a flyby manoeuvre over the Imhotep-Khepry transition in April 2016. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 observations with mainly three broadband filters (centered at 480, 649, and 743 nm) at a resolution of up to 0.53 m/px and for phase angles between 0.095 degrees and 62 degrees. Aims. We have investigated the morphological and spectrophotometrical properties of this area using the OSIRIS/NAC high-resolution observations. Methods. We assembled the observations into coregistered color cubes. Using a 3D shape model, we produced the illumination conditions and georeference for each observation. We mapped the observations of the transition to investigate its geomorphology. Observations were photometrically corrected using the Lommel-Seeliger disk law. Spectrophotometric analyses were performed on the coregistered color cubes. These data were used to estimate the local phase reddening. Results. The Imhotep-Khepry transition hosts numerous and varied types of terrains and features. We observe an association between a feature's nature, its reflectance, and its spectral slopes. Fine material deposits exhibit an average reflectance and spectral slope, while terrains with diamictons, consolidated material, degraded outcrops, or features such as somber boulders present a lower-than-average reflectance and higher-than-average spectral slope. Bright surfaces present here a spectral behavior consistent with terrains enriched in water-ice. We find a phase-reddening slope of 0.064 +/- 0.001%/100 nm/degrees at 2.7 au outbound, similar to the one obtained at 2.3 au inbound during the February 2015 flyby. Conclusions. Identified as the source region of multiple jets and a host of water-ice material, the Imhotep-Khepry transition appeared in April 2016, close to the frost line, to further harbor several potential locations with exposed water-ice material among its numerous different morphological terrain units.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, Laboratoire d'Astrophysique de Marseille, France, Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, Universidad Politechnica de Madrid, Spain, Department of Physics and Astronomy of Uppsala University, Sweden, and Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES, and ASI. The SPICE libraries and PDS resources are developed and maintained by NASA. The authors thank the referee and editors for their questions, remarks, and advices for the improvement of this article.
Published: 2019

27. Phase-curve analysis of comet 67P/Churyumov-Gerasimenko at small phase angles

Author: D. Bodewits, Marco Fulle, Monica Lazzarin, Jakob Deller, Giampiero Naletto, V. Da Deppo, Nafiseh Masoumzadeh, Stefano Debei, Mohamed Ramy El-Maarry, Detlef Koschny, Björn Davidsson, H. U. Keller, Cecilia Tubiana, J. J. Lopez-Moreno, Imre Toth, W-H. Ip, M. A. Barucci, Pedro Hasselmann, Gabriele Cremonese, Ludmilla Kolokolova, Sonia Fornasier, Colin Snodgrass, M. De Cecco, Pedro J. Gutiérrez, Xian Shi, Carsten Güttler, Ivano Bertini, Francesco Marzari, L. M. Lara, Stefano Mottola, Holger Sierks, R. Rodrigo, P. L. Lamy, J. L. Bertaux, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Earth and Planetary Sciences [UCL/Birkbeck], Birkbeck College [University of London], DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), California Institute of Technology (CALTECH)-NASA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), and Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
Subjects: Asteroiden und Kometen, Study phase, 010504 meteorology & atmospheric sciences, publications, bibliography, Comet, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – techniques: photometric – techniques: image processing, Individual, Image processing, techniques: image processing, Coherent backscattering, Astrophysics, 7. Clean energy, 01 natural sciences, photometric [techniques], techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Comets, publications, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, image processing [techniques], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Phase angle, bibliography - techniques, general [Comets], bibliography, Astronomy and Astrophysics, Phase curve, 67P/Churyumov-Gerasimenko - publications, bibliography - techniques, General - comets, Photometric - techniques, Computational physics, Comets: general, Wavelength, Space and Planetary Science, Phase ratio, 67P/Churyumov-Gerasimenko - publications, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., The Rosetta-OSIRIS images acquired at small phase angles in three wavelengths during the fly-by of the spacecraft on 9-10 April 2016 provided a unique opportunity to study the opposition effect on the surface of comet 67P/Churyumov-Gerasimenko (67P). Our goal is to study phase curves of the nucleus at small phase angles for a variety of surface structures to show the differences in their opposition effect and to determine which surface properties cause the differences.© N. Masoumzadeh et al. 2019, OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany; the CISAS University of Padova, Italy; the Laboratoire d'Astrophysique de Marseille, France; the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain; the Research and Scientific Support Department of the ESA, Noordwijk, Netherlands; the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain; the Universidad Politechnica de Madrid, Spain; the Department of Physics and Astronomy of Uppsala University, Sweden; and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Operations Centre and the Rosetta Mission Operations Centre for the successful rendezvous with comet 67P/Churyumov-Gerasimenko. This research has made use of the USGS Integrated Software for Imagers and Spectrometers (ISIS). We gratefully acknowledge the developers of SPICE and NAIF/PDS resources. This research has made use of the scientific software shapeViewer www.comet-toolbox.com.L.K.acknowledges a support from the NASA SSW grant 80NSSC17K0731.
Published: 2019

28. Gas outflow and dust transport of comet 67P/Churyumov–Gerasimenko

Author: Francesco Marzari, Wing-Huen Ip, Laurent Jorda, J. Rainer Kramm, Hans Rickman, Gábor L. Kovács, Marc Hofmann, I. L. Lai, Philippe Lamy, Detlef Koschny, Jong-Shinn Wu, Mariolino De Cecco, Nilda Oklay, Ivano Bertini, Michael Küppers, Xian Shi, Nicolas Thomas, Stubbe F. Hviid, Jean-Loup Bertaux, Holger Sierks, C. Güttler, Olivier Groussin, Vania Da Deppo, Marco Fulle, Steven Boudreault, Pedro J. Gutiérrez, Giampiero Naletto, M. A. Barucci, Horst Uwe Keller, Michael F. A'Hearn, Jose J. Lopez Moreno, Jui Chi Lee, Ying Liao, Cesare Barbieri, Luisa Lara, Monica Lazzarin, Cheng Chin Su, Jean-Baptiste Vincent, Jakob Deller, Gabriele Cremonese, Ekkehard Kührt, Zhong-Yi Lin, Björn Davidsson, Cecilia Tubiana, Stefano Debei, Jessica Agarwal, Sonia Fornasier, Jörg Knollenberg, Rafael Rodrigo, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Department of Atmospheric Sciences [Taoyuan City], Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), ITA, USA, GBR, FRA, and DEU
Subjects: individual: comet 67P/Churyumov-Gerasimenko [comets], 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet dust, Irregular shape, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, general [comets], methods: numerical, Astronomi, astrofysik och kosmologi, 0103 physical sciences, Comets: general, Comets: individual: comet 67P/Churyumov-Gerasimenko, Methods: numerical, Astronomy and Astrophysics, Space and Planetary Science, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Jet (fluid), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Comet tail, 520 Astronomy, comets: general, Thermal cycle, Astronomy, numerical [methods], comets: individual: comet 67P/Churyumov-Gerasimenko, 620 Engineering, 13. Climate action, Outflow, Astrophysics::Earth and Planetary Astrophysics
Abstract: International audience; Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov–Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.
Published: 2016

29. Exploiting Local Persistency for Reduced State Space Generation

Author: Kamel Barkaoui, Zhiwu Li, Hanifa Boucheneb, CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), Laboratoire VeriForm - Department of Computer Engineering (VeriForm), École Polytechnique de Montréal (EPM), Xidian University, Macau University of Science and Technology (MUST), Atig M., Bensalem S., Bliudze S., and Monsuez B. (eds)
Subjects: [INFO.INFO-CC]Computer Science [cs]/Computational Complexity [cs.CC], Computer science, 020207 software engineering, 02 engineering and technology, Petri net, Set (abstract data type), Order (business), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, [INFO]Computer Science [cs], State space generation, Algorithm, ComputingMilieux_MISCELLANEOUS, Parametric statistics
Abstract: This paper deals with the partial order techniques of Petri nets, based on persistent sets and step graphs. To take advantage of the strengths of each method, it proposes the persistent step sets as a parametric combination of the both methods. The persistent step sets method allows to fix, for each marking, the set of transitions to be covered by the selected steps and then to control their maximal length and number. Moreover, this persistent step selective search preserves, at least, deadlocks of Petri nets.
Published: 2018

30. OSSOS. VII. 800+ Trans-Neptunian Objects—The Complete Data Release

Author: Pierre Vernazza, Sarah Greenstreet, Cory Shankman, Michael Marsset, Wing-Huen Ip, Rebekah I. Dawson, Ruth Murray-Clay, Marian Jakubik, Rosemary E. Pike, Michele T. Bannister, Pedro Lacerda, Audrey Thirouin, Patryk Sofia Lykawka, Brett Gladman, Matthew J. Lehner, Mike Alexandersen, Christa Van Laerhoven, Hsing Wen Lin, Aurélie Guilbert-Lepoutre, Mikael Granvik, Kathryn Volk, R. Lynne Jones, Samantha Lawler, Susan D. Benecchi, Nahuel Cabral, Audrey Delsanti, Stephen D. J. Gwyn, Megan E. Schwamb, Nathan A. Kaib, Shiang-Yu Wang, Jean-Marc Petit, Philippe Rousselot, Ying-Tung Chen, J. J. Kavelaars, Edward Ashton, Wesley C. Fraser, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Helsinki], Falculty of Science [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), University of Helsinki-University of Helsinki, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), NRC Herzberg Astronomy and Astrophysics, Conseil National de Recherches Canada (CNRC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Lowell Observatory [Flagstaff], Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Department of Physics
Subjects: Solar System, 010504 meteorology & atmospheric sciences, MIGRATION, Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, KUIPER-BELT OBJECTS, Ephemeris, NEPTUNE, 01 natural sciences, SOLAR-SYSTEM, surveys, Neptune, 0103 physical sciences, Trans-Neptunian object, education, 010303 astronomy & astrophysics, Minor planet, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, JUPITER, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, TROJANS, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], ORIGIN, Giant planet, Astronomy, Astronomy and Astrophysics, general [Kuiper belt], RESONANCE, 115 Astronomy, Space science, Orbit, URANUS, 13. Climate action, Space and Planetary Science, DISCOVERY, Kuiper belt: general, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The Outer Solar System Origins Survey (OSSOS), a wide-field imaging program in 2013-2017 with the Canada-France-Hawaii Telescope, surveyed 155 deg$^{2}$ of sky to depths of $m_r = 24.1$-25.2. We present 838 outer Solar System discoveries that are entirely free of ephemeris bias. This increases the inventory of trans-Neptunian objects (TNOs) with accurately known orbits by nearly 50%. Each minor planet has 20-60 Gaia/Pan-STARRS-calibrated astrometric measurements made over 2-5 oppositions, which allows accurate classification of their orbits within the trans-Neptunian dynamical populations. The populations orbiting in mean-motion resonance with Neptune are key to understanding Neptune's early migration. Our 313 resonant TNOs, including 132 plutinos, triple the available characterized sample and include new occupancy of distant resonances out to semi-major axis $a \sim 130$ au. OSSOS doubles the known population of the non-resonant Kuiper belt, providing 436 TNOs in this region, all with exceptionally high-quality orbits of $a$ uncertainty $\sigma_{a} \leq 0.1\%$; they show the belt exists from $a \gtrsim 37$ au, with a lower perihelion bound of $35$ au. We confirm the presence of a concentrated low-inclination $a\simeq 44$ au "kernel" population and a dynamically cold population extending beyond the 2:1 resonance. We finely quantify the survey's observational biases. Our survey simulator provides a straightforward way to impose these biases on models of the trans-Neptunian orbit distributions, allowing statistical comparison to the discoveries. The OSSOS TNOs, unprecedented in their orbital precision for the size of the sample, are ideal for testing concepts of the history of giant planet migration in the Solar System., Comment: Invited paper, special issue Data: Insights and Challenges in a Time of Abundance. Data tables and example survey simulator are in the supplementary materials (see arXiv source under Downloads > Other formats)
Published: 2018

31. Hardy-Hodge Decomposition of Vector Fields in R$^{n}$

Author: Laurent Baratchart, Tao Qian, Pei Dang, Analyse fonctionnelle pour la conception et l'analyse de systèmes (FACTAS), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Macau University of Science and Technology (MUST), and University of Macau (UMac)
Subjects: Pure mathematics, quaternionic analysis, General Mathematics, Vector decomposition, 010103 numerical & computational mathematics, Astrophysics::Cosmology and Extragalactic Astrophysics, [MATH.MATH-CA]Mathematics [math]/Classical Analysis and ODEs [math.CA], 01 natural sciences, harmonic gradients, vector field decomposition, Mathematics - Analysis of PDEs, Classical Analysis and ODEs (math.CA), FOS: Mathematics, Astrophysics::Solar and Stellar Astrophysics, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], 0101 mathematics, Complex Variables (math.CV), Astrophysics::Galaxy Astrophysics, Mathematics, Mathematics - Complex Variables, Applied Mathematics, Hodge decomposition, [MATH.MATH-CV]Mathematics [math]/Complex Variables [math.CV], 010101 applied mathematics, Mathematics - Classical Analysis and ODEs, Vector field, Astrophysics::Earth and Planetary Astrophysics, Analysis of PDEs (math.AP)
Abstract: We prove that a $IR n+1$-valued vector field on IR n is the sum of the traces of two harmonic gradients, one in each component of $IR n+1 \ IR n$ , and of a $IR n$-valued divergence free vector field. We apply this to the description of vanishing potentials in divergence form. The results are stated in terms of Clifford Hardy spaces, the structure of which is important for our study., Comment: to appear in Transactions of the American Mathematical Society
Published: 2018

32. Tensile strength of 67P/Churyumov–Gerasimenko nucleus material from overhangs

Author: Attree , N., Groussin , O., Jorda , L., Nébouy , D., Thomas , N., Brouet , Y., Kührt , E., Preusker , F., Scholten , F., Knollenberg , J., Hartogh , P., Sierks , H., Barbieri , C., Lamy , P., Rodrigo , R., Koschny , D., Rickman , H., Keller , H. U., A'Hearn , M. F., Auger , A.-T., Barucci , M. A., Bertaux , J.-L., Bertini , I., Bodewits , D., Boudreault , S., Cremonese , G., Da Deppo , V., Davidsson , B., Debei , S., De Cecco , M., Deller , J., El-Maarry , M. R., Fornasier , S., Fulle , M., Gutiérrez , P. J., Güttler , C., Hviid , S., Ip , W.-H., Kovacs , G., Kramm , J. R., Küppers , M., Lara , L. M., Lazzarin , M., Lopez Moreno , J. J., Lowry , S., Marchi , S., Marzari , F., Mottola , S., Naletto , G., Oklay , N., Pajola , M., Toth , I., Tubiana , C., Vincent , J.-B., Shi , X., A’Hearn , M., Gutierrez , J., Lara , M., Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Physikalisches Institut [Bern], Universität Bern [Bern], DLR Institute of Planetary Research, German Aerospace Center ( DLR ), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Research and Scientific Support Department, ESTEC ( RSSD ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ) -European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Department of Astronomy [College Park], University of Maryland [College Park], Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Istituto Nazionale di Astrofisica ( INAF ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Department of Physics and Astronomy [Uppsala], Uppsala University, INAF - Osservatorio Astronomico di Trieste ( OAT ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Space Science Institute [Macau] ( SSI ), Macau University of Science and Technology ( MUST ), European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), Centre for Astrophysics and Planetary Science [Canterbury] ( CAPS ), University of Kent [Canterbury], Solar System Exploration Research Virtual Institute ( SSERVI ), Southwest Research Institute [Boulder] ( SwRI ), Istituto Nazionale di Fisica Nucleare, Sezione di Padova ( INFN, Sezione di Padova ), National Institute for Nuclear Physics ( INFN ), Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Institute for Nanoscale Physics and Chemistry ( INPAC ), and Katholieke Universiteit Leuven ( KU Leuven )
Subjects: Methods: observational, comets: general, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], comets: individual: Churyumov-Gerasimenko
Abstract: International audience; We directly measured twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimated the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around 1 Pa or less (1 to 5 Pa, when scaled to a metre length). The presence of eroded material at the base of most overhangs, as well as the observed collapse of two features andthe implied previous collapse of another, suggests that they are prone to failure and that the true material strengths are close to these lower limits (although we only consider static stresses and not dynamic stress from, for example, cometary activity). Thus, a tensile strength of a few pascals is a good approximation for the tensile strength of the 67P nucleus material, which is in agreement with previous work. We find no particular trends in overhang properties either with size over the 10-100 m range studied here or location on the nucleus. There are no obvious differences, in terms of strength, height or evidence of collapse, between the populations of overhangs on the two cometary lobes, suggesting that 67P is relatively homogenous in terms of tensile strength. Low material strengths are supportive of cometary formation as a primordial rubble pile or by collisional fragmentation of a small body (tens of km).
Published: 2018

33. Meter-scale thermal contraction crack polygons on the nucleus of comet 67P/Churyumov-Gerasimenko

Author: Auger , A.-T., Groussin , O., Jorda , L., El-Maarry , M. R., Bouley , S., Sejourne , A., Gaskell , R., Capanna , C., Davidsson , B., Marchi , S., Höfner , S., Lamy , P. L., Sierks , H., Barbieri , C., Rodrigo , R., Koschny , D., Rickman , H., Keller , H. U., Agarwal , J., A'Hearn , M. F., Barucci , M. A., Bertaux , J.-L., Bertini , I., Cremonese , G., Da Deppo , V., Debei , S., De Cecco , M., Fornasier , S., Fulle , M., Gutiérrez , P. J., Güttler , C., Hviid , S., Ip , W.-H., Knollenberg , J., Kramm , J.-R., Kührt , E., Küppers , M., Lara , L. M., Lazzarin , M., Lopez Moreno , J. J., Marzari , F., Massironi , M., Michalik , H., Naletto , G., Oklay , N., Pommerol , A., Sabau , L., Thomas , N., Tubiana , C., Vincent , J.-B., Wenzel , K.-P., Lamy , L., A’Hearn , M., Barucci , A., BERTAUX , L., Gutierrez , J., Ip , H., Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Physikalisches Institut [Bern], Universität Bern [Bern], Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Interactions et dynamique des environnements de surface ( IDES ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Planetary Science Institute [Tucson] ( PSI ), Department of Physics and Astronomy [Uppsala], Uppsala University, Solar System Exploration Research Virtual Institute ( SSERVI ), Southwest Research Institute [Boulder] ( SwRI ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Research and Scientific Support Department, ESTEC ( RSSD ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ) -European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), European Space Agency ( ESA ), Department of Astronomy [College Park], University of Maryland [College Park], Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Istituto Nazionale di Astrofisica ( INAF ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), INAF - Osservatorio Astronomico di Trieste ( OAT ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), DLR Institute of Planetary Research, German Aerospace Center ( DLR ), Space Science Institute [Macau] ( SSI ), Macau University of Science and Technology ( MUST ), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), European Space Astronomy Center ( ESAC ), Istituto Nazionale di Fisica Nucleare, Sezione di Padova ( INFN, Sezione di Padova ), National Institute for Nuclear Physics ( INFN ), Dipartimento di Geoscienze [Padova], Institut für Datentechnik und Kommunikationsnetze, Technische Universität Braunschweig [Braunschweig], Instituto Nacional de Técnica Aeroespacial ( INTA ), Institute for Nanoscale Physics and Chemistry ( INPAC ), and Katholieke Universiteit Leuven ( KU Leuven )
Subjects: Comets, Geological processes, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Nucleus, [ SDU ] Sciences of the Universe [physics], [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]
Abstract: International audience; We report on the detection and characterization of more than 6300 polygons on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, using images acquired by the OSIRIS camera onboard Rosetta between August 2014 and March 2015. They are found in consolidated terrains and grouped in localized networks. They are present at all latitudes (from North to South) and longitudes (head, neck, and body), sometimes on pit walls or following lineaments. About 1.5% of the observed surface is covered by polygons. Polygons have an homogeneous size across the nucleus, with 90% of them in the size range 1 - 5 m and a mean size of 3.0 ± 1.4 m. They show different morphologies, depending on the width and depth of their trough. They are found in networks with 3- or 4-crack intersection nodes. The polygons observed on 67P are consistent with thermal contraction crack polygons formed by the diurnal or seasonal temperature variations in a hard (MPa) and consolidated sintered layer of water ice, located a few centimeters below the surface. Our thermal analysis shows an evolution of thermal contraction crack polygons according to the local thermal environment, with more evolved polygons (i.e. deeper and larger troughs) where the temperature and the diurnal and seasonal temperature range are the highest. Thermal contraction crack polygons are young surface morphologies that probably formed after the injection of 67P in the inner solar system, typically 100,000 years ago, and could be as young as a few orbital periods, following the decreasing of its perihelion distance in 1959 from 2.7 to 1.3 a.u. Meter scale thermal contraction crack polygons should be common features on the nucleus of Jupiter family comets.
Published: 2018

34. IoT-based smart and complex systems: a guest editorial report

Author: Xiaoou Li, Zhiwu Li, MengChu Zhou, Kamel Barkaoui, Tadahiko Murata, Naiqi Wu, Macau University of Science and Technology (MUST), Xidian University, CEDRIC. Systèmes sûrs (CEDRIC - SYS), Centre d'études et de recherche en informatique et communications (CEDRIC), Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Ecole Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise (ENSIIE)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), Departamento de Control Automático (CINVESTAV-IPN), Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), Kansai University, New Jersey Institute of Technology [Newark] (NJIT), Space Science Institute [Macau] (SSI), School of Electronic Engineering [Xidian University] (SEE), and Department of Computer Science Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN) Mexico City, Mexico (CINVESTAV-IPN)
Subjects: 0209 industrial biotechnology, business.industry, Information storage, Second Industrial Revolution, 020206 networking & telecommunications, 02 engineering and technology, Per capita income, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 020901 industrial engineering & automation, Commerce, Artificial Intelligence, Control and Systems Engineering, Muscle power, 0202 electrical engineering, electronic engineering, information engineering, The Internet, [INFO]Computer Science [cs], Internet of Things, business, Industrial Revolution, Productivity, ComputingMilieux_MISCELLANEOUS, Information Systems
Abstract: The Industrial Revolution starting from about 1760 and ending at around 1840 has been viewed as the first Industrial Revolution. It features with the replacement of human and animal muscle power with steam and mechanical power. Human income per capita had taken 800 years to double by the early 1800’s. Since 1760, the first Industrial Revolution spent only about 150 years to increase human income per capita by thirteen-fold. While historians are still debating what the second Industrial Revolution is, many believe that it is Internet Revolution. It started in about 60 years ago. It features the applications of computing, communications, and networking and information storage in every aspect of human life. It offers even much faster growth of human income per capita and drastically promoted industrial productivity.
Published: 2018

35. The big lobe of 67P/Churyumov–Gerasimenko comet: morphological and spectrophotometric evidences of layering as from OSIRIS data

Author: P. J. Gutierrez, Xian Shi, Carsten Güttler, Pedro Hasselmann, J. J. López-Moreno, Matteo Massironi, Monica Lazzarin, Detlef Koschny, Stubbe F. Hviid, M. A. Barucci, Björn Davidsson, Cecilia Tubiana, Ivano Bertini, Pamela Cambianica, Nicolas Thomas, Michael Küppers, Francesca Ferri, Luca Penasa, Francesco Marzari, M. De Cecco, W-H. Ip, J. L. Bertaux, Marco Franceschi, Laurent Jorda, Holger Sierks, J.-B. Vincent, Olivier Groussin, E. Frattin, F. La Forgia, Stefano Debei, Philippe Lamy, Jakob Deller, Maurizio Pajola, Nilda Oklay, Giampiero Naletto, Ekkehard Kührt, Sonia Fornasier, L. M. Lara, V. Da Deppo, Marco Fulle, Jörg Knollenberg, Emanuele Simioni, Sabrina Ferrari, R. Rodrigo, Gabriele Cremonese, Alice Lucchetti, H. U. Keller, Dennis Bodewits, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Fundacion Galileo Galilei, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Center for Space and Habitability (CSH), University of Bern, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Ferrari, Sabrina, Penasa, L., La Forgia, F., Massironi, M., Naletto, G., Lazzarin, M., Fornasier, S., Hasselmann, P. H., Lucchetti, A., Pajola, M., Ferri, F., Cambianica, Pamela, Oklay, N., Tubiana, C., Sierks, H., Lamy, P. L., Rodrigo, R., Koschny, D., Davidsson, B., Barucci, M. A., Bertaux, J. -L., Bertini, I., Bodewits, D., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Deller, J., Franceschi, M., Frattin, Elisa, Fulle, M., Groussin, O., Gutiérrez, P. J., Güttler, C., Hviid, S. F., Ip, W. -H., Jorda, L., Keller, H. U., Knollenberg, J., Kührt, E., Küppers, M., Lara, L. M., López-Moreno, J. J., Marzari, F., Shi, X., Simioni, E., Thomas, N., Vincent, J. -B., Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, Brightness, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Techniques: image processing, Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Multispectral image, Comet, Data analysis, Mineralogy, Spatial distribution, 01 natural sciences, Texture (geology), Image processing, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, medicine, Comets, image processing [Techniques], spectral variegation, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], biology, OSIRIS cameras, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, general [Comets], Astronomy and Astrophysic, biology.organism_classification, 620 Engineering, Lobe, data analysi [Methods], medicine.anatomical_structure, multiple-filters, Variegation (histology), Osiris
Abstract: Between 2014 and 2016, ESA's Rosetta OSIRIS cameras acquired multiple-filters images of the layered nucleus of comet 67P/Churyumov-Gerasimenko, ranging from ultraviolet to near-infrared wavelengths. No correlation between layers disposition and surface spectral variegation has been observed so far. This paper investigates possible spectral differences among decametre-thickness outcropping layers of the biggest lobe of the comet by means of OSIRIS image dataset. A two-classes maximum likelihood classification was applied on consolidated outcrops and relative deposits identified on post-perihelion multispectral images of the big lobe. We distinguished multispectral data on the basis of the structural elevation of the onion-shell Ellipsoidal Model of 67P. The spatial distribution of the two classes displays a clear dependence on the structural elevation, with the innermost class resulting over 50 per cent brighter than the outermost one. Consolidated cometarymaterials located at different structural levels are characterized by different brightness and revealed due to the selective removal of large volumes. This variegation can be attributed to a different texture of the outcrop surface and/or to a different content of refractory materials.© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society., We are grateful to Paul Helfenstein for corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Goottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission.
Published: 2018

36. Regional unit definition for the nucleus of comet 67P/Churyumov-Gerasimenko on the SHAP7 model

Author: Holger Sierks, J.-B. Vincent, F. Preusker, Giampiero Naletto, Francesco Marzari, Sonia Fornasier, Stubbe F. Hviid, M. A. Barucci, P. J. Gutierrez, Carsten Güttler, J. J. Lopez-Moreno, Jörg Knollenberg, Ivano Bertini, Stefano Debei, V. Da Deppo, P. L. Lamy, Frank Scholten, Detlef Koschny, Björn Davidsson, W-H. Ip, Marco Fulle, Nicolas Thomas, M. R. El Maarry, Cecilia Tubiana, Monica Lazzarin, Ekkehard Kührt, L. M. Lara, Raphael Marschall, J. L. Bertaux, H. U. Keller, Dennis Bodewits, R. Rodrigo, Laurent Jorda, G. Cremonese, M. De Cecco, P. Theologou, Olivier Groussin, ITA, USA, GBR, FRA, DEU, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Swiss National Science Foundation, European Commission, and State Secretariat for Education, Research and Innovation (Switzerland)
Subjects: 67P/Churyumov-Gerasimenko, Morphology, Surface (mathematics), 010504 meteorology & atmospheric sciences, Comet, Geometry, Surface finish, Table (information), 01 natural sciences, Nucleus, Computer graphics, Rosetta, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Subdivision, Astronomy and Astrophysics, Space and Planetary Science, business.industry, 520 Astronomy, 620 Engineering, medicine.anatomical_structure, es, [SDU]Sciences of the Universe [physics], business, Unit (ring theory), Geology
Abstract: Open Acces publication. This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed., The previously defined regions on the nucleus of comet 67P/Churyumov-Gerasimenko have been mapped back onto the 3D SHAP7 model of the nucleus (Preusker et al., 2017). The resulting regional definition is therefore self-consistent with boundaries that are well defined in 3 dimensions. The facets belonging to each region are provided as supplementary material. The shape model has then been used to assess inhomogeneity of nucleus surface morphology within individual regions. Several regions show diverse morphology. We propose sub-division of these regions into clearly identifiable units (sub-regions) and a comprehensive table is provided. The surface areas of each sub-region have been computed and statistics based on grouping of unit types are provided. The roughness of each region is also provided in a quantitative manner using a technique derived from computer graphics applications. The quantitative method supports the sub-region definition by showing that differences between sub-regions can be numerically justified.© 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2.
Published: 2018
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37. Models of Rosetta/OSIRIS 67P Dust Coma Phase Function

Author: Giovanna Rinaldi, Jean-Loup Bertaux, Carsten Güttler, Marco Fulle, Xian Shi, Giampiero Naletto, Jessica Agarwal, Stefano Mottola, Dominique Bockelée-Morvan, Olga Muñoz, Holger Sierks, F. Moreno, V. V. Zakharov, Francesco Marzari, M. De Cecco, V. Della Corte, Stavro Ivanovski, E. Frattin, Detlef Koschny, L. M. Lara, Björn Davidsson, Cecilia Tubiana, Wing-Huen Ip, Philippe Lamy, Ivano Bertini, S. Fornasier, H. U. Keller, Ludmilla Kolokolova, Monica Lazzarin, Gabriele Cremonese, J. J. López-Moreno, Alessandra Rotundi, Dennis Bodewits, Stefano Debei, Imre Tóth, D. Guirado, P. J. Gutierrez, Jakob Deller, Zhong-Yi Lin, M. A. Barucci, R. Rodrigo, V. Da Deppo, Polish Academy of Sciences, Ministerio de Economía y Competitividad (España), European Commission, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), National Central University [Taiwan] (NCU), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), and Technische Universität Braunschweig [Braunschweig]
Subjects: methods: numerical, minor planets, asteroids: individual (67P/Churyumov-Gerasimenko), Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Phase function, asteroids: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, asteroids: individual (67P), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Mission operations, numerical [Methods], biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], asteroids: individual (67P Churyumov–Gerasimenko), biology.organism_classification, individual (67P/Churyumov-Gerasimenko) [Minor planets,asteroids], minor planets, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Minor planets,asteroids: individual (67P/Churyumov-Gerasimenko), Astrophysics - Earth and Planetary Astrophysics
Abstract: The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images. This function shows a deep minimum at phase angles near 100°, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly oriented aggregate particles. We show, however, that an ensemble of oriented elongated particles of a wide variety of aspect ratios, with radii r 10 μm, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60%-70% range.© 2018. The American Astronomical Society. All rights reserved.., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire dAstrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politecnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB; grant No. 74/10: 2), and the ESA Technical Directorate is gratefully acknowledged. H.R. was also supported by grant No. 2011/01/B/ST9/05442 of the Polish National Science Center. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. This work was supported by contracts AYA2015-67152-R and AYA2015-71975-REDT from the Spanish Ministerio de Economia y Competitividad.
Published: 2018

38. Online Fault Diagnosis of Discrete Event Systems Modeled With Labeled Petri Nets Using an Overall Fault Status

Author: Zhu, Guanghui, Feng, Lei, Li, Zhiwu, Wu, Naiqi, Xidian University, Modèles et Formalismes à Evénements Discrets (MOFED), Laboratoire d'Informatique et Systèmes (LIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Metacohorts Consortium, Royal Institute of Technology [Stockholm] (KTH ), Department of Industrial Engineering, School of Electromechanical Engineering [Guangzhou], Guangdong University of Science and Technology (GUST)-Guangdong University of Science and Technology (GUST), and Macau University of Science and Technology (MUST)
Subjects: Overall fault status, Integer linear programming, [INFO.INFO-AU]Computer Science [cs]/Automatic Control Engineering, Hardware_PERFORMANCEANDRELIABILITY, Petri net, Discrete event system, Fault diagnosis, [SPI.AUTO]Engineering Sciences [physics]/Automatic
Abstract: REPORT OF LABORATOIRE D’INFORMATIQUE ET SYSTÈMES (LIS), AIX-MARSEILLE UNIVERSITÉ, MARSEILLE, FRANCE; In this paper we present a fault diagnosis approach using labeled Petri nets, where the faults are modeled by unobservable transitions and the unobservable subnet is acyclic. In contrast to detecting the individual faults separately, a new specification called an overall fault status is introduced, which indicates the occurrence of faults from a global system perspective. Due to the introduction of the overall fault status, a more precise and informative diagnosis result can be provided and in some cases, the occurrence of some faults in a system can be detected before the actual faults are isolated, i.e., we are certain about the occurrence of faults but which faults have not been ascertained. An integer linear programming (ILP) problem is built according to the observed word. We prove that all transition sequences determined by solutions to the ILP problem constitute the set of sequences consistent with the observed word. By specifying different objective functions to the ILP problem, the diagnosis results of each individual fault and the overall fault status can be obtained. An online diagnosis algorithm is developed to implement the proposed diagnosis process, which reports the diagnosis results after the occurrence of every observable event.
Published: 2018

39. Prototype of the gas chromatograph-mass spectrometer to investigate volatile species in the lunar soil for the Luna-Resurs mission

Author: A. G. Sapgir, Peter Wurz, Arnaud Buch, Davide Lasi, Patrice Coll, Marek Tulej, L. Hofer, M. Gerasimov, David Coscia, Cyril Szopa, Michel Cabane, Physikalisches Institut [Bern], Universität Bern [Bern], Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Universität Bern [Bern] (UNIBE), IMPEC - LATMOS, and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Detection limit, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Analytical chemistry, Astronomy and Astrophysics, Mass spectrometry, Regolith, 13. Climate action, Space and Planetary Science, Mass spectrum, Calibration, Lunar soil, Environmental science, Gas chromatography, Gas chromatography–mass spectrometry
Abstract: In preparation for the Russian Luna Resurs mission we combined our compact time of flight mass spectrometer (TOF MS) with a chemical pre separation of the species by gas chromatography (GC). Coupled measurements with both instruments were successfully performed with the prototype of the mass spectrometer and a flight like gas chromatograph. The system was tested with two test gas mixtures a mixture of hydrocarbons and a mixture of noble gases. Due to its capability to record mass spectra over the full mass range at once with high sensitivity and a dynamic range of up to 10(6) within 1 s the TOF MS system is a valuable extension of the GC analytical system. Based on the measurements with calibration gases performed with the combined GC MS prototype and under assumption of mean characteristics for the Moon's regolith the detection limit for volatile species in a soil sample is estimated to 2.10( 10) by mass for hydrocarbons and 2.10( 9) by mass for noble gases. (C) 2015 Elsevier Ltd. All rights reserved.
Published: 2015
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40. Whole-genome analyses resolve early branches in the tree of life of modern birds

Author: Bhanu Rekepalli, Jaime Huerta-Cepas, David Haussler, Beth Shapiro, Frank E. Rheindt, Bo Li, Per Alström, Oliver A. Ryder, Salvador Capella-Gutierrez, Jianwen Li, José Alfredo Samaniego, Binghang Liu, Paula F. Campos, David P. Mindell, Xiangjiang Zhan, An Pas, Yinhua Huang, Liang Liu, Scott V. Edwards, Dave Burt, David A. Ray, Andrew Dixon, Hui Li, Toni Gabaldón, Bastien Boussau, Cai Li, Hans Ellegren, Carsten Rahbek, Shengbin Li, Michael J. Braun, Peter Houde, Peter V. Lovell, Alexandros Stamatakis, Claudia C. Weber, Yong Zhang, Jian Wang, Thomas Sicheritz-Pontén, Volodymyr Zavidovych, Alexander Suh, Xiong Yinqi, Maria Paula Cruz Schneider, Stephen J. O'Brien, Ganesh Ganapathy, Shamsuzzoha Bayzid, Huanming Yang, Guojie Zhang, Alonzo Alfaro-Núñez, Claudio V. Mello, Michael Bunce, Amy C. Driskell, Francisco Prosdocimi, Zijun Xiong, Joel Cracraft, Long Zhou, Mikkel H. Schierup, Brant C. Faircloth, Gary R. Graves, F. Keith Barker, Jon Fjeldså, Benoit Nabholz, Bent E. K. Lindow, Frederick H. Sheldon, Robb T. Brumfield, Nitish Narula, Bent O. Petersen, Kasper Munch, Klaus-Peter Koepfli, Rute R. da Fonseca, Thomas L. Bailey, Kui Wu, Quiemei Zheng, Tandy Warnow, John E. McCormack, Elizabeth P. Derryberry, Linnéa Smeds, Simon Y. W. Ho, Polina L. Perelman, Siavash Mirarab, Qi Zhou, Michael William Bruford, Knud A. Jønsson, M. Thomas P. Gilbert, Ning Li, Richard E. Green, Edward L. Braun, R. Paul Scofield, Wesley C. Warren, Zhenyu Li, Fang Zhang Zhang, Warren E. Johnson, Morgan Wirthlin, Jason T. Howard, Travis C. Glenn, Ludovic Orlando, Mads F. Bertelsen, David M. Lambert, Andre J. Aberer, Erich D. Jarvis, Sankar Subramanian, Amhed Missael Vargas Velazquez, Yongli Zeng, Eske Willerslev, Jin Xiao, Shiping Liu, Wang Jun, Howard Hughes Medical Institute (HHMI), Duke University Medical Center, University of Texas at Austin [Austin], Heidelberg Institute for Theoretical Studies (HITS ), Beijing Genomics Institute [Shenzhen] (BGI), Xi'an Jiaotong University (Xjtu), Natural History Museum of Denmark, Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), New Mexico State University, The University of Sydney, University of California, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Evolutionary Biology Centre (EBC), Uppsala University, Okinawa Institute of Science and Technology Graduate University, University of Georgia [USA], Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Griffith University [Brisbane], Centre for Genomic Regulation [Barcelona] (CRG), Universitat Pompeu Fabra [Barcelona] (UPF)-Centro Nacional de Analisis Genomico [Barcelona] (CNAG), Institució Catalana de Recerca i Estudis Avançats (ICREA), Joint Institute for Computational Sciences [Knoxville] (JICS), The University of Tennessee [Knoxville], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Aarhus University [Aarhus], The McDonnell Genome Institute (MGI), Washington University in Saint Louis (WUSTL), Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology [Mstate, USA] (BCH-EPP), Mississippi State University [Mississippi], Department of Biological Sciences [Lubbock], Texas Tech University [Lubbock] (TTU), Department of Ecology and Evolutionary Biology [Santa Cruz], University of California [Santa Cruz] (UCSC), University of California-University of California, School of Biosciences [Cardiff], Cardiff University, Kunming Institute of Zoology, Chinese Academy of Sciences [Beijing] (CAS), International Wildlife Consultants Ltd, China Agricultural University (CAU), Tulane University, Louisiana State University (LSU), Copenhagen Zoo, Oregon Health and Science University [Portland] (OHSU), Federal University of Para - Universidade Federal do Para [Belem - Brésil], Technical University of Denmark [Lyngby] (DTU), Breeding Centre for Endangered Arabian Wildlife, Dubai Hospital, Canterbury Museum, Curtin University [Perth], Planning and Transport Research Centre (PATREC), Department of Integrative Biology [Berkeley] (IB), University of California [Berkeley], National Cancer Institute Frederick, Novosibirsk State University (NSU), Smithsonian Institution, Department of Biological Sciences [Singapore], National University of Singapore (NUS), Bell Museum of Natural History, University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Department of Life Sciences, Imperial College London, Smithsonian Conservation Biology Institute, Theodosius Dobzhansky Center for Genome Bioinformatics, St Petersburg State University (SPbU), Nova Southeastern University (NSU), Center for Biomolecular Science and Engineering, San Diego Zoo Global Institute for Conservation Research, Occidental College, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Key Laboratory of Zoological Systematics and Evolution, Chinese Academy of Agricultural Sciences (CAAS), Swedish Species Information Centre, Swedish University of Agricultural Sciences (SLU), Department of Organismic and Evolutionary Biology [Cambridge] (OEB), Harvard University [Cambridge], Institute of Theoretical Informatics, Karlsruhe Institute of Technology (KIT), Department of Biochemistry and Biophysics [San Francisco], American Museum of Natural History (AMNH), University of Florida [Gainesville] (UF), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, University of Copenhagen = Københavns Universitet (KU), King Abdulaziz University, Macau University of Science and Technology (MUST), The University of Hong Kong (HKU), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), University of California (UC), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Kunming Institute of Zoology (KIZ), Federal University of Para - Universidade Federal do Pará - UFPA [Belém, Brazil] (UFPA), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), University of California [Berkeley] (UC Berkeley), Biotechnology and Biological Sciences Research Council (BBSRC), Harvard University, and University of Copenhagen = Københavns Universitet (UCPH)
Subjects: Palaeognathae, MESH: Sequence Analysis, DNA, Genetic Speciation, MESH: Introns, Zoology, MESH: Biological Evolution, MESH: Base Sequence, Article, Coalescent theory, Avian Proteins, Birds, MESH: INDEL Mutation, INDEL Mutation, MESH: Avian Proteins, Animals, MESH: Animals, MESH: Genome, MESH: Phylogeny, Clade, Phylogeny, MESH: Genetic Speciation, Genome, Multidisciplinary, Columbea, Base Sequence, biology, Phylogenetic tree, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Sequence Analysis, DNA, Passerea, biology.organism_classification, Biological Evolution, Introns, MESH: Genes, [SDV.GEN.GA]Life Sciences [q-bio]/Genetics/Animal genetics, Genes, MESH: DNA Transposable Elements, Neognathae, MESH: Birds, DNA Transposable Elements, Neoaves
Abstract: International audience; To better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species. Among Passerea, we infer the common ancestor of core landbirds to have been an apex predator and confirm independent gains of vocal learning. Among Columbea, we identify pigeons and flamingoes as belonging to sister clades. Even with whole genomes, some of the earliest branches in Neoaves proved challenging to resolve, which was best explained by massive protein-coding sequence convergence and high levels of incomplete lineage sorting that occurred during a rapid radiation after the Cretaceous-Paleogene mass extinction event about 66 million years ago.
Published: 2014

41. A three-dimensional modelling of the layered structure of comet 67P/Churyumov-Gerasimenko

Author: Hans Rickman, Matteo Massironi, J.-R. Kramm, Ivano Bertini, Stubbe F. Hviid, Francesco Marzari, P. J. Gutierrez, M. De Cecco, Emanuele Simioni, Ekkehard Kührt, L. M. Lara, Frank Scholten, Detlef Koschny, Cesare Barbieri, Maurizio Pajola, R. Rodrigo, V. Da Deppo, Jakob Deller, Frank Preusker, S. Fornasier, Monica Lazzarin, Jean-Baptiste Vincent, Giampiero Naletto, Francesca Ferri, Robert Gaskell, Jessica Agarwal, Wing-Huen Ip, J-C. Lee, Laurent Jorda, N. Thomas, M. A. Barucci, Björn Davidsson, Michael Küppers, Alice Lucchetti, M. F. A'Hearn, Clement Feller, Marc Hofmann, Cecilia Tubiana, Olivier Groussin, Stefano Debei, Gabriele Cremonese, Holger Sierks, Marco Fulle, Philippe Lamy, Sabrina Ferrari, J. J. Lopez Moreno, F. La Forgia, Nilda Oklay, Carsten Güttler, E. Frattin, Luca Penasa, J. L. Bertaux, H. U. Keller, Jörg Knollenberg, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Astronomia [Padova], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), DLR Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universita degli Studi di Padova-Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: 010504 meteorology & atmospheric sciences, Geometry, Concentric, Classification of discontinuities, 01 natural sciences, Layered structure, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Comets: general, Methods: data analysis, Physics, [PHYS]Physics [physics], comets: individual: 67P/Churyumov–Gerasimenko, comets: general, Astronomy and Astrophysics, Dimensional modeling, Ellipsoid, methods: data analysis, Lobe, medicine.anatomical_structure, Space and Planetary Science, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Free parameter
Abstract: International audience; We provide a three-dimensional model of the inner layered structure of comet 67P based on the hypothesis of an extended layering independently wrapping each lobe. A large set of terrace orientations was collected on the latest shape model and then used as a proxy for the local orientation of the surfaces of discontinuity which defines the layers. We modelled the terraces as a family of concentric ellipsoidal shells with fixed axis ratios, producing a model that is completely defined by just eight free parameters. Each lobe of 67P has been modelled independently, and the two sets of parameters have been estimated by means of non-linear optimization of the measured terrace orientations. The proposed model is able to predict the orientation of terraces, the elongation of cliffs, the linear traces observed in the Wosret and Hathor regions and the peculiar alignment of boulder-like features which has been observed in the Hapi region, which appears to be related to the inner layering of the big lobe. Our analysis allowed us to identify a plane of junction between the two lobes, further confirming the independent nature of the lobes. Our layering models differ from the best-fitting topographic ellipsoids of the surface, demonstrating that the terraces are aligned to an internal structure of discontinuities, which is unevenly exposed on the surface, suggesting a complex history of localized material removal from the nucleus.
Published: 2017

42. The pristine interior of comet 67P revealed by the combined Aswan outburst and cliff collapse

Author: Frank Scholten, Frank Preusker, M. F. A'Hearn, Monica Lazzarin, Ekkehard Kührt, Harald Michalik, Olivier Groussin, Nilda Oklay, Jean-Baptiste Vincent, Luca Penasa, Detlef Koschny, M. De Cecco, Nicolas Thomas, Matteo Massironi, Imre Toth, V. Da Deppo, J. L. Bertaux, Laurent Jorda, Holger Sierks, Björn Davidsson, Carsten Güttler, Emanuele Simioni, Steve Boudreault, Stubbe F. Hviid, S. Höfner, Géza Kovács, Cecilia Tubiana, Sonia Fornasier, Marc Hofmann, Mohamed Ramy El-Maarry, Francesco Marzari, J.-R. Kramm, J. J. Lopez Moreno, Hans Rickman, Maurizio Pajola, Gabriele Cremonese, Giampiero Naletto, Sebastien Besse, M. A. Barucci, Pedro Hasselmann, Michael Küppers, Jörg Knollenberg, Luisa Lara, J. D. P. Deshapriya, Stefano Debei, Francesca Ferri, Rafael Rodrigo, Antoine Pommerol, Jessica Agarwal, H. U. Keller, Cesare Barbieri, Philippe Lamy, Jakob Deller, Zhong-Yi Lin, Stephen C. Lowry, P. J. Gutierrez, Ivano Bertini, W-H. Ip, Clement Feller, Emanuele Baratti, Marco Fulle, Sabrina Ferrari, Alice Lucchetti, Stefano Mottola, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Department of Civil Chemical Environmental and Materials Engineering [Bologna] (DICAM), University of Bologna/Università di Bologna, Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], and University of Bologna
Subjects: outburst, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Escarpment, 01 natural sciences, Aswan, comet, Rosetta, 0103 physical sciences, Cliff, Table (landform), 010303 astronomy & astrophysics, QB, 0105 earth and related environmental sciences, Physics, geography, 67P, geography.geographical_feature_category, biology, cliff, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, Crust, Landslide, Albedo, biology.organism_classification, collapse, WAC, 13. Climate action, Osiris, Comet 67/P
Abstract: International audience; Outbursts occur commonly on comets1 with different frequencies and scales2,3. Despite multiple observations suggesting various triggering processes4,5, the driving mechanism of such outbursts is still poorly understood. Landslides have been invoked6 to explain some outbursts on comet 103P/Hartley 2, although the process required a pre-existing dust layer on the verge of failure. The Rosetta mission observed several outbursts from its target comet 67P/Churyumov–Gerasimenko, which were attributed to dust generated by the crumbling of materials from collapsing cliffs7,8. However, none of the aforementioned works included definitive evidence that landslides occur on comets. Amongst the many features observed by Rosetta on the nucleus of the comet, one peculiar fracture, 70 m long and 1 m wide, was identified on images obtained in September 2014 at the edge of a cliff named Aswan9. On 10 July 2015, the Rosetta Navigation Camera captured a large plume of dust that could be traced back to an area encompassing the Aswan escarpment7. Five days later, the OSIRIS camera observed a fresh, sharp and bright edge on the Aswan cliff. Here we report the first unambiguous link between an outburst and a cliff collapse on a comet. We establish a new dust-plume formation mechanism that does not necessarily require the breakup of pressurized crust or the presence of supervolatile material, as suggested by previous studies7. Moreover, the collapse revealed the fresh icy interior of the comet, which is characterized by an albedo >0.4, and provided the opportunity to study how the crumbling wall settled down to form a new talus.The evolution of the collapse of the Aswan cliff9, observed by the OSIRIS Narrow Angle Camera (NAC)10 and the Rosetta Navigation camera (NavCam), is shown in Fig. 1. We estimated a total outburst ejected mass of cometary material between 0.5 × 106 and 1.0 × 106 kg for the 10 July event. By applying stereo-photogrammetric methods11 using multiple OSIRIS images (Supplementary Table 1), we determined the total volume of material that collapsed from the Aswan cliff. In Fig. 2, the dataset that depicts the aspect of the cliff before and after the collapse is presented. By using pre- and post-collapse three-dimensional (3D) models (see Methods), we have been able to measure the dimensions of the collapsed overhang (Supplementary Figs 1–2), deriving a total volume of 2.20 × 104 m3, with a 1σ uncertainty of 0.34 × 104 m3.
Published: 2017

43. Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography

Author: E. Kuehrt, Luca Penasa, Giampiero Naletto, Marco Fulle, A. Gicquel, Cesare Barbieri, Francesco Marzari, J. L. Bertaux, Stefano Mottola, Ivano Bertini, F. Preusker, Carsten Güttler, Jakob Deller, Gabriele Cremonese, Zhong-Yi Lin, F. Scholten, Géza Kovács, Hans Rickman, Steve Boudreault, Monica Lazzarin, Jörg Knollenberg, L. M. Lara, V. Da Deppo, M. A. Barucci, Michael Küppers, Holger Sierks, Stubbe F. Hviid, Detlef Koschny, J. J. Lopez Moreno, M. De Cecco, P. Gutiérrez-Marquez, Nicolas Thomas, Björn Davidsson, Cecilia Tubiana, Xian Shi, Imre Toth, N. Oklay, Philippe Lamy, Stefano Debei, Maurizio Pajola, X. Hu, Wing-Huen Ip, J. B. Vincent, J.-R. Kramm, Laurent Jorda, Sonia Fornasier, D. de Niem, Marc Hofmann, P. J. Gutierrez, Clement Feller, R. Rodrigo, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Information Engineering [Padova] (DEI), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Dipartimento di Geoscienze [Padova], Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), NASA-California Institute of Technology (CALTECH), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), and Universität Bern [Bern] (UNIBE)
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, Distribution (number theory), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, comet, surface evolution, topography, statistical analysis, Rosetta, 0103 physical sciences, Statistical analysis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], 67P, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Comets: individual: 67P, Astronomy and Astrophysics, Geophysics, Comets: general, 620 Engineering, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a statistical analysis of the distribution of large-scale topographic features on comet 67P/Churyumov-Gerasimenko.We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 ± 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the Northern hemisphere topography is dominated by structures on the 100 m scale, while the Southern hemisphere topography, illuminated at perihelion, is dominated by 10 m scale terrain features. Our study suggests that the current size of a cliff is controlled not only by material cohesion but also by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height-power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, that is, its evolutionary age. © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Published: 2017

44. Results and Analysis of ChaLearn LAP Multi-modal Isolated and Continuous Gesture Recognition, and Real versus Fake Expressed Emotions Challenges

Author: Wan, Jun, Escalera, Sergio, Anbarjafari, Gholamreza, Escalante, Hugo, Baró, Xavier, Guyon, Isabelle, Madadi, Meysam, Allik, Jüri, Lin, Chi, Xie, Yiliang, Guyon, Isabelle, National Laboratory of Pattern Recognition [Beijing] (NLPR), Institute of Automation - Chinese Academy of Sciences, Computer Vision Center (Centre de visio per computador) (CVC), Universitat Autònoma de Barcelona (UAB), University of Tartu, Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), TAckling the Underspecified (TAU), Laboratoire de Recherche en Informatique (LRI), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and Macau University of Science and Technology (MUST)
Subjects: [INFO.INFO-AI] Computer Science [cs]/Artificial Intelligence [cs.AI], [INFO.INFO-CV] Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], [INFO.INFO-NE] Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], [INFO.INFO-LG] Computer Science [cs]/Machine Learning [cs.LG], [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI]
Abstract: International audience; We analyze the results of the 2017 ChaLearn Looking at People Challenge at ICCV. The challenge comprised three tracks: (1) large-scale isolated (2) continuous gesture recognition, and (3) real versus fake expressed emotions tracks. It is the second round for both gesture recognition challenges, which were held first in the context of the ICPR 2016 workshop on " multimedia challenges beyond visual analysis ". In this second round, more participants joined the competitions, and the performances considerably improved compared to the first round. Particularly, the best recognition accuracy of isolated gesture recognition has improved from 56.90% to 67.71% in the IsoGD test set, and Mean Jaccard Index (MJI) of continuous gesture recognition has improved from 0.2869 to 0.6103 in the ConGD test set. The third track is the first challenge on real versus fake expressed emotion classification, including six emotion categories, for which a novel database was introduced. The first place was shared between two teams who achieved 67.70% averaged recognition rate on the test set. The data of the three tracks, the participants' code and method descriptions are publicly available to allow researchers to keep making progress in the field.
Published: 2017

45. Enterotypes in the landscape of gut microbial community composition

Author: Curtis Huttenhower, Ian B. Jeffery, Howard Ochman, George M. Weinstock, Fredrik Bäckhed, S. Dusko Ehrlich, Paul W. O'Toole, David A. Relman, Martin J. Blaser, Georg Zeller, Jun Wang, Christopher Quince, Rob Knight, Liping Zhao, Masahira Hattori, Dan Knights, Fergus Shanahan, Ruth E. Ley, Gary D. Wu, Falk Hildebrand, Jeroen Raes, Peer Bork, Paul I. Costea, Claire M. Fraser, Willem M. de Vos, James D. Lewis, Frederic D. Bushman, Shinichi Sunagawa, Manimozhiyan Arumugam, European Molecular Biology Laboratory (EMBL), Vrije Universiteit Brussel (VUB), Flanders Institute for Biotechnology, Novo Nordisk Foundation Center for Basic Metabolic Research (CBMR), Faculty of Health and Medical Sciences, University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), University of Copenhagen = Københavns Universitet (KU), University of Gothenburg (GU), New York University Langone Medical Center (NYU Langone Medical Center), NYU System (NYU), University of Pennyslvania, University of Helsinki, Laboratory of Microbiology, Wageningen University and Research [Wageningen] (WUR), MetaGenoPolis, Institut National de la Recherche Agronomique (INRA), Centre for Host-Microbiome Interactions, Dental Institute Central Office, Guy’s Hospital, King‘s College London, University of Maryland School of Medicine, University of Maryland System, Waseda University, Harvard School of Public Health, APC Microbiome Institute [Cork], University College Cork (UCC), University of Minnesota [Twin Cities] (UMN), University of Minnesota System, Department of Computer Science and Engineering, University of Minnesota System-University of Minnesota System, Max Planck Institute for Developmental Biology, Max-Planck-Gesellschaft, Department of Integrative Biology [Berkeley] (IB), University of California [Berkeley], University of California-University of California, Warwick Medical School, University of Warwick [Coventry], Stanford University, Veterans Affairs Palo Alto Health Care System, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Biology, Northern Arizona University [Flagstaff], Princess Al Jawhara Albrahim Center of Excellence in the Research of Hereditary Disorders, King Abdulaziz University, Macau University of Science and Technology (MUST), Department of Medicine and State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong (HKU), The Jackson Laboratory [Bar Harbor] (JAX), Shanghai Jiao Tong University School of Medicine, Université Catholique de Louvain = Catholic University of Louvain (UCL), University of Colorado, University of Colorado [Boulder], Department of Chemistry and Biochemistry [Boulder], University of Colorado Anschutz [Aurora], Molecular Medicine Partnership Unit, Heidelberg University, Max Delbrück Center for Molecular Medicine [Berlin] (MDC), Helmholtz-Gemeinschaft = Helmholtz Association, EMBL, VIB, Rega institute for Medical Research, MicrobesInside [250172], European Community's Seventh Framework Programme via the MetaHIT [HEALTH-F4-2007-201052], METACARDIS project [FP7-HEALTH-2012-INNOVATION-I-305312], European Union's Horizon research and innovation programme (Marie Sklodowska-Curie grant) [600375], Metagenopolis grant [ANR-11-DPBS-0001], IHMS project [FP7-HEALTH-2010-single-stage-261376], European Project: 268985,EC:FP7:ERC,ERC-2010-AdG_20100317,CANCERBIOME(2011), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), University of Copenhagen = Københavns Universitet (UCPH), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Waseda University [Tokyo, Japan], University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: 0301 basic medicine, Microbiology (medical), 16S, [SDV]Life Sciences [q-bio], 030106 microbiology, Immunology, Applied Microbiology and Biotechnology, Microbiology, Article, diversity, 03 medical and health sciences, Human health, Human gut, bacteroides, Clinical Research, Microbiologie, RNA, Ribosomal, 16S, Genetics, Life Science, Animals, Humans, Microbiome, genes, VLAG, Ribosomal, human intestinal microbiota, Bacteria, Human Genome, association, Environmental ethics, Biodiversity, Cell Biology, infection, Bacterial Typing Techniques, Gastrointestinal Microbiome, Gastrointestinal Tract, Clinical Practice, Geography, age, Community composition, Medical Microbiology, Metagenomics, prevotella, RNA, Metagenome, Enterotype, diet, metabolism
Abstract: International audience; Population stratification is a useful approach for a better understanding of complex biological problems in human health and wellbeing. The proposal that such stratification applies to the human gut microbiome, in the form of distinct community composition types termed enterotypes, has been met with both excitement and controversy. In view of accumulated data and re-analyses since the original work, we revisit the concept of enterotypes, discuss different methods of dividing up the landscape of possible microbiome configurations, and put these concepts into functional, ecological and medical contexts. As enterotypes are of use in describing the gut microbial community landscape and may become relevant in clinical practice, we aim to reconcile differing views and encourage a balanced application of the concept.
Published: 2017

46. Investigating the physical properties of outbursts on comet 67P/Churyumov-Gerasimenko

Author: I. L. Lai, W-H. Ip, Xian Shi, Holger Sierks, Stefano Mottola, Ivano Bertini, Laurent Jorda, Dennis Bodewits, Michael Küppers, Detlef Koschny, Marc Hofmann, M. A. Barucci, J. L. Bertaux, P. J. Gutierrez, Carsten Güttler, M. De Cecco, Nilda Oklay, R. Rodrigo, Jessica Agarwal, Giampiero Naletto, B. J. R. Davidsson, Esther Drolshagen, V. Da Deppo, N. Thomas, Cesare Barbieri, Philippe Lamy, Géza Kovács, Theresa Ott, Jakob Deller, Stubbe F. Hviid, Marco Fulle, Zhong-Yi Lin, J.-R. Kramm, Hans Rickman, Cecilia Tubiana, J-C. Lee, Monica Lazzarin, J. J. López-Moreno, Jean-Baptiste Vincent, Francesco Marzari, Jörg Knollenberg, Sonia Fornasier, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, Ekkehard Kührt, L. M. Lara, Stefano Debei, Gabriele Cremonese, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], Department of Information Engineering [Padova] (DEI), University of Oldenburg, Physikalisches Institut [Bern], Universität Bern [Bern], Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrobiology, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, comets: individual: 67P/Churyumov–Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business
Abstract: Cometary outbursts on several comets have been observed both by ground-based telescopes and by in situ instruments on spacecraft. However, the mechanism behind these phenomena and their physical properties are still unclear. The optical, spectrocopic and infrared remote imaging system (OSIRIS) onboard the Rosetta spacecraft provided first-hand information on the outbursts from comet 67P/Churyumov-Gerasimenko during its perihelion passage in 2015. The physical properties of the outbursts can be investigated by examining the time series of these high-resolution images. An analysis is made of the wide- and narrow-angle images obtained during the monitoring of the outburst sequences, which occurred between July and September in 2015. A ring-masking technique is used to calculate the excess brightness of the outbursts. The ejected mass and expansion velocity of the outbursts is estimated from differences in images made with the same filter (orange filter). The calculated excess brightness from these outburst plumes ranges from a few per cent to 28 per cent. In some major outbursts, the brightness contribution from the outburst plume can be one or two times higher than that of the typical coma jet activities. The strongest event was the perihelion outburst detected just a few hours before perihelion. The mass ejection rate during a generic outburst could reach a few per cent of the steady-state value of the dust coma. Transient events are detected by studying the brightness slope of the outburst plume with continuous streams of outflowing gas and dust triggered by driving mechanisms, as yet not understood, which remain active for several minutes to less than a few hours.
Published: 2017

47. Characterization of dust aggregates in the vicinity of the Rosetta spacecraft

Author: Wing-Huen Ip, Carsten Güttler, Marco Fulle, Detlef Koschny, Nicolas Thomas, Laurent Jorda, Yuan Li, Nilda Oklay, H. U. Keller, J.-R. Kramm, J.-B. Vincent, Pedro Hasselmann, Cesare Barbieri, P. Gutiérrez Marqués, V. Da Deppo, Marc Hofmann, Sonia Fornasier, Ivano Bertini, Jakob Deller, Holger Sierks, P. J. Gutierrez, M. De Cecco, J. L. Bertaux, Michael Küppers, M. F. A'Hearn, Francesco Marzari, Olivier Groussin, Jörg Knollenberg, Björn Davidsson, Maurizio Pajola, J. J. López-Moreno, Jessica Agarwal, R. Rodrigo, Cecilia Tubiana, Theresa Ott, Bernhard Geiger, Stubbe F. Hviid, Géza Kovács, Monica Lazzarin, Giampiero Naletto, M. A. Barucci, Steve Boudreault, Dennis Bodewits, Esther Drolshagen, Xian Shi, Stefano Mottola, Ekkehard Kührt, L. M. Lara, Hans Rickman, Stefano Debei, Gabriele Cremonese, Philippe Lamy, Swedish National Space Board, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), European Space Agency, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Oldenburg, Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], NASA Ames Research Center (ARC), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Carl Von Ossietzky Universität Oldenburg, Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Image processing, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Comets: general, Comets: individual: 67P/ Churyumov-Gerasimenko, Astrobiology, Physics::Plasma Physics, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Rosetta, Comets, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Dynamic motion, Physics, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, biology, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, general [Comets], Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Characterization (materials science), Space and Planetary Science, Physics::Space Physics, Particle, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: In a Rosetta/OSIRIS imaging activity in 2015 June, we have observed the dynamic motion of particles close to the spacecraft. Due to the focal setting of the OSIRIS wide angle camera, these particles were blurred, which can be used to measure their distances to the spacecraft. We detected 109 dust aggregates over a 130 min long sequence, and find that their sizes are around a millimetre and their distances cluster between 2 and 40 m from the spacecraft. Their number densities are about a factor 10 higher than expected for the overall coma and highly fluctuating. Their velocities are small compared to the spacecraft orbital motion and directed away from the spacecraft, towards the comet. From this we conclude that they have interacted with the spacecraft and assess three possible scenarios. In the likeliest of the three scenarios, centimetre-sized aggregates collide with the spacecraft and we would observe the fragments. Ablation of a dust layer on the spacecraft's z panel (remote instrument viewing direction) when rotated towards the Sun is a reasonable alternative. We could also measure an acceleration for a subset of 18 aggregates, which is directed away from the Sun and can be explain by a rocket effect, which requires a minimum ice fraction of the order of 0.1 per cent.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017

48. The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations

Author: Pedro Hasselmann, Philippe Lamy, Clement Feller, J. L. Bertaux, Xian Shi, M. F. A'Hearn, Olivier Groussin, M. De Cecco, Maurizio Pajola, M. L. Lara, J.-C. Lee, J.-B. Vincent, Holger Sierks, Stefano Mottola, Nilda Oklay, Marco Fulle, Wing-Huen Ip, Laurent Jorda, Cesare Barbieri, Imre Toth, Lorenza Giacomini, M. A. Barucci, Carsten Güttler, Jakob Deller, Sabrina Ferrari, V. Da Deppo, J. J. Lopez Moreno, Zhong-Yi Lin, Marc Hofmann, Sonia Fornasier, Detlef Koschny, Ivano Bertini, H. U. Keller, Nicolas Thomas, Michael Küppers, Jörg Knollenberg, Jessica Agarwal, Rafael Rodrigo, Giampiero Naletto, J. D. P. Deshapriya, Stefano Debei, Ekkehard Kührt, Géza Kovács, Gabriele Cremonese, Monica Lazzarin, Francesco Marzari, P. J. Gutiérrez, R. Kramm, Björn Davidsson, Matteo Massironi, Cecilia Tubiana, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: observational, Techniques: photometric, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Outcrop, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Fault scarp, 01 natural sciences, Mantle (geology), 0103 physical sciences, Spectral slope, OSIRIS, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy, Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Plume, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 13. Climate action, Space and Planetary Science, Layering, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits, and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur/Bes boundary during/after the perihelion passage, close to the area where exposed CO$_2$ and H$_2$O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit, and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers., 16 pages, 15 figures, published online on 24 May 2017 on Mon. Not. R. Astron. Soc. stx1275, https://doi.org/10.1093/mnras/stx1275
Published: 2017

49. Dust mass distribution around comet 67P/Churyumov–Gerasimenko determined via parallax measurements using Rosetta's OSIRIS cameras

Author: J.-R. Kramm, P. J. Gutiérrez, M. F. A'Hearn, Olivier Groussin, J.-B. Vincent, Cesare Barbieri, E. Frattin, J. J. López-Moreno, Björn Poppe, Jakob Deller, M. De Cecco, Detlef Koschny, Nilda Oklay, Giampiero Naletto, Maurizio Pajola, Steve Boudreault, Zhong-Yi Lin, Clement Feller, V. Da Deppo, Marco Fulle, J. L. Bertaux, Géza Kovács, P. I. Lamy, Carsten Güttler, Wing-Huen Ip, Laurent Jorda, Francesco Marzari, E. Drolshagen, Stubbe F. Hviid, M. A. Barucci, Ivano Bertini, Marc Hofmann, Hans Rickman, Holger Sierks, Björn Davidsson, Jörg Knollenberg, Cecilia Tubiana, Monica Lazzarin, H. U. Keller, Jessica Agarwal, Bernhard Geiger, Michael Küppers, Sonia Fornasier, Xian Shi, T. Ott, Stefano Mottola, R. Rodrigo, A. Gicquel, Nicolas Thomas, Gabriele Cremonese, Ekkehard Kührt, L. M. Lara, Stefano Debei, University of Oldenburg, Carl Von Ossietzky Universität Oldenburg, Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Physikalisches Institut [Bern], Universität Bern [Bern], Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), NASA-California Institute of Technology (CALTECH), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Ministerio de Economía y Competitividad (España), Swedish National Space Board, European Space Agency, Centre National de la Recherche Scientifique (France), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Coma (optics), 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Rosetta, 0103 physical sciences, Spectral slope, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Parallaxes, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Range (particle radiation), Mass distribution, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, general [Comets], Astronomy, Astronomy and Astrophysics, 620 Engineering, Space and Planetary Science, Particle, Parallax, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The OSIRIS (optical, spectroscopic and infrared remote imaging system) instrument on board the ESA Rosetta spacecraft collected data of 67P/Churyumov-Gerasimenko for over 2 yr. OSIRIS consists of two cameras, a Narrow Angle Camera and a Wide Angle Camera. For specific imaging sequences related to the observation of dust aggregates in 67P's coma, the two cameras were operating simultaneously. The two cameras are mounted 0.7 m apart from each other, as a result this baseline yields a parallax shift of the apparent particle trails on the analysed images directly proportional to their distance. Thanks to such shifts, the distance between observed dust aggregates and the spacecraft was determined. This method works for particles closer than 6000 m to the spacecraft and requires very few assumptions. We found over 250 particles in a suitable distance range with sizes of some centimetres, masses in the range of 10-10 kg and a mean velocity of about 2.4 m s relative to the nucleus. Furthermore, the spectral slope was analysed showing a decrease in the median spectral slope of the particles with time. The further a particle is from the spacecraft the fainter is its signal. For this reason, this was counterbalanced by a debiasing. Moreover, the dust mass-loss rate of the nucleus could be computed as well as the Af ρ of the comet around perihelion. The summed-up dust mass-loss rate for the mass bins 10-10 kg is almost 8300 kg s.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017

50. Distance determination method of dust particles using Rosetta OSIRIS NAC and WAC data

Author: Ivano Bertini, Björn Poppe, Marco Fulle, Nilda Oklay, V. Da Deppo, M. De Cecco, Monica Lazzarin, J. J. Lopez Moreno, Wing-Huen Ip, Laurent Jorda, Clement Feller, J.-R. Kramm, Theresa Ott, P. Lamy, P. J. Gutierrez, R. Rodrigo, Esther Drolshagen, A. Gicquel, Detlef Koschny, Marc Hofmann, Xian Shi, Jessica Agarwal, M. F. A'Hearn, Olivier Groussin, Stubbe F. Hviid, Francesco Marzari, Cesare Barbieri, Gabriele Cremonese, J. L. Bertaux, Jakob Deller, Ekkehard Kührt, Hans Rickman, L. M. Lara, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, H. U. Keller, Stefano Debei, Holger Sierks, M. A. Barucci, Giampiero Naletto, Jörg Knollenberg, Sonia Fornasier, Michael Küppers, Nicolas Thomas, Carl Von Ossietzky Universität Oldenburg, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Akademie der Wissenschaften zu Göttingen, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Offset (computer science), 010504 meteorology & atmospheric sciences, Infrared, Dust particles, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Rosetta, 0103 physical sciences, Comets, Dust, Parallax, Stereo observations, Astronomy and Astrophysics, Space and Planetary Science, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Spacecraft, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], business.industry, 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, biology.organism_classification, 620 Engineering, stereo observations, Computer Science::Computer Vision and Pattern Recognition, Physics::Space Physics, 67 P/Churyumov-Gerasimenko, dust, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67 P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust particles in the comet's coma, the two cameras took images at the same time.The aim of this work is to use these simultaneous double camera observations to calculate the dust particles’ distance to the spacecraft. As the two cameras are mounted on the spacecraft with an offset of 70 cm, the distance of particles observed by both cameras can be determined by a shift of the particles’ apparent trails on the images. This paper presents first results of the ongoing work, introducing the distance determination method for the OSIRIS instrument and the analysis of an example particle. We note that this method works for particles in the range of about 500 m – 6000 m from the spacecraft.
Published: 2017
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