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101 results on '"Frank Scholten"'

1. Application of Implicit <scp>3D</scp> Modelling to Reconstruct the Layered Structure of the Comet <scp>67P</scp>

Author: Penasa, Luca, Massironi, Matteo, Emanuele, Simioni, Franceschi, Marco, Naletto, Giampiero, Ferrari, Sabrina, Bertini, Ivano, Pamela, Cambianica, Frattin, Elisa, LA FORGIA, Fiorangela, Alice, Lucchetti, Maurizio, Pajola, Frank, Preusker, Frank, Scholten, Laurent, Jorda, Robert, Gaskell, and Holger, Sierks
Published: 2022
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2. Concern-oriented analysis and refactoring of software architectures using dependency structure matrices.

Author: Bedir Tekinerdogan, Frank Scholten, Christian Hofmann, and Mehmet Aksit
Published: 2009
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3. Stereo Vision Based Reconstruction of Huge Urban Areas from an Airborne Pushbroom Camera (HRSC).

Author: Heiko Hirschmüller, Frank Scholten, and Gerd Hirzinger
Published: 2005
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4. Characterization of the MASCOT landing area by Hayabusa2

Author: Stefan Schröder, Naoya Sakatani, Rie Honda, Eri Tatsumi, Yasuhiro Yokota, Deborah Domingue, Yuichiro Cho, Shingo Kameda, Kohei Kitazato, Toru Kouyama, Moe Matsuoka, Akira Miura, Tomokatsu Morota, Tatsuaki Okada, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Seiji Sugita, Satoshi Tanaka, Hikaru Yabuta, Manabu Yamada, Matthias Grott, Maximilian Hamm, Tra-Mi Ho, Ralf Jaumann, Stefano Mottola, Katharina Otto, Nicole Schmitz, and Frank Scholten
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, asteroids: individual: Ryugu – methods: data analysis, FOS: Physical sciences, Astronomy and Astrophysics, Geology, methods: data analysis, asteroids: individual: Ryugu, individual: Ryugu [asteroids], Astronomi, astrofysik och kosmologi, Space and Planetary Science, minor planets, data analysis [methods], Astronomy, Astrophysics and Cosmology, Geologi, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. After landing on C-type asteroid Ryugu, MASCOT imaged brightly colored, submillimeter-sized inclusions in a small rock. Hayabusa2 successfully returned a sample of small particles from the surface of Ryugu, but none of these appear to harbor such inclusions. The samples are considered representative of Ryugu. Aims. To understand the apparent discrepancy between MASCOT observations and Ryugu samples, we assess whether the MASCOT landing site, and the rock by implication, is perhaps atypical for Ryugu. Methods. We analyzed observations of the MASCOT landing area acquired by three instruments on board Hayabusa2: a camera (ONC), a near-infrared spectrometer (NIRS3), and a thermal infrared imager. We compared the landing area properties thus retrieved with those of the average Ryugu surface. Results. We selected several areas and landforms in the landing area for analysis: a small crater, a collection of smooth rocks, and the landing site itself. The crater is relatively blue and the rocks are relatively red. The spectral and thermophysical properties of the landing site are very close to those of the average Ryugu surface. The spectral properties of the MASCOT rock are probably close to average, but its thermal inertia may be somewhat higher. Conclusions. The MASCOT rock can also be considered representative of Ryugu. Some of the submillimeter-sized particles in the returned samples stand out because of their atypical spectral properties. Such particles may be present as inclusions in the MASCOT rock.
Published: 2022

5. Application of Implicit Modelling to Reconstruct the Layered Structure of the Comet 67P

Author: Luca, Penasa, Matteo, Massironi, Emanuele, Simioni, Franceschi, Marco, Giampiero, Naletto, Sabrina, Ferrari, Bertini, Ivano, Pamela, Cambianica, Elisa, Frattin, Fiorangela La Forgia, Alice, Lucchetti, Maurizio, Pajola, Frank, Preusker, Frank, Scholten, Laurent, Jorda, Robert, Gaskell, Holger, Sierks, Andrea Bistacchi, Matteo Massironi, Sophie Viseur, Penasa, Luca, Massironi, Matteo, Simioni, Emanuele, Franceschi, Marco, Naletto, Giampiero, Ferrari, Sabrina, Bertini, Ivano, Cambianica, Pamela, Frattin, Elisa, La Forgia, Fiorangela, Lucchetti, Alice, Pajola, Maurizio, Preusker, Frank, Scholten, Frank, Jorda, Laurent, Gaskell, Robert, and Sierks, Holger
Abstract: We provide details about the procedure employed for the three-dimensional geological modelling of the lobes of comet Churyumov-Gerasimenko (67P). The two lobes of 67P are characterized by well visible terraces and elongated cliffs that revealed a pervasive layering arranged in an onion-like fashion. None of the layers can be traced for a continuity large enough to provide a means of stratigraphic correlation. Therefore, an explicit modelling approach of the layered structure is not easily applicable. We show how a very simple modelling strategy based on implicitly-defined analytical surfaces (spheres or ellipsoids), and requiring very limited operator decision-making, can be successfully applied to produce a geological model that easily fits the available scattered attitude observations. Our formulation has the advantage of providing a small set of parameters with a precise geometrical meaning that can be compared with other parameters of the lobes (i.e. center of ellipsoids and center of mass). The presented method originates outside commercial geological modelling software packages and required devising some ad-hoc solutions for the visualization of the resulting models in comparison with observations made on OSIRIS images. Some extracts of the visualization code, helpful for applying this procedure in similar operational contexts, are also presented.
Published: 2022

6. Attitude reconstruction of MASCOT lander during its descent and stay on asteroid (162173) Ryugu

Author: Romain Garmier, Yuya Mimasu, Yuichi Tsuda, Elisabet Canalias, Ralf Jaumann, Thierry Martin, Aurelie Moussi, Tra-Mi Ho, Laurence Lorda, Frank Scholten, Jens Biele, and Alex Torres
Subjects: Scientific instrument, 010504 meteorology & atmospheric sciences, Spacecraft, Computer science, business.industry, Astronomy and Astrophysics, 01 natural sciences, Mascot, Aeronautics, Flight dynamics, asteroid Ryugu, Space and Planetary Science, Asteroid, 0103 physical sciences, Trajectory, MASCOT lander, Descent (aeronautics), business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Hayabusa-2, a JAXA mission, reached C-type asteroid (162173) Ryugu in June 2018. Hayabusa2 carried MASCOT (Ho et al., 2016), a small lander developed by DLR and CNES. The goal of MASCOT was to perform in situ measurements on the surface of the asteroid by means of its four scientific instruments, substantially contributing in this way to the overall scientific return of Hayabusa2 mission. MASCOT landing occurred the October 3, 2018. After its release by Hayabusa2 spacecraft, the MASCOT lander experienced 17 min of descent and bounces. Then after stabilization it collected measurements during 17 h, visiting three slightly different sites. A comprehensive knowledge of MASCOT’s attitudes on the various moment of its mission is essential for the understanding of the science data gathered by the scout. CNES flight dynamics team was involved in the reconstruction of MASCOT landing trajectory and attitude. This paper presents the attitude reconstruction of MASCOT during its descent and on its second landing site. The reconstruction used as inputs the housekeeping data generated by the 6 Photo Electric Cells of MASCOT, as well as the images acquired by Hayabusa2 ONC camera and the MASCAM camera. The assessment was very complex but we determined the attitude with a mean accuracy around 10° during descent and 8° when MASCOT was stable once the second landing site was successfully reached. Nevertheless, for the other phases - bounces, first landing site and last landing site-the lander attitude is still undetermined.
Published: 2021

7. Surface roughness of asteroid (162173) Ryugu and comet 67P/Churyumov-Gerasimenko inferred from in-situ observations

Author: Kosuke Yoshioka, Hidehiko Suzuki, Tra-Mi Ho, Frank Preusker, Eri Tatsumi, Frank Trauthan, Hirotaka Sawada, Nicole Schmitz, Alexander Koncz, Rutu Parekh, Katharina A. Otto, Katrin Krohn, Frank Scholten, K-D Matz, Manabu Yamada, K. Ogawa, Stefan Schröder, Shingo Kameda, Toru Kouyama, C. Honda, Ralf Jaumann, Masahiko Hayakawa, Stefano Mottola, Naoya Sakatani, Tomokatsu Morota, Rie Honda, Katrin Stephan, Seiji Sugita, Yuichiro Cho, Moe Matsuoka, and Y. Yokota
Subjects: asteroids, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Geometry, &/P/Churyumov-Gerasimenko, Surface finish, 01 natural sciences, Fractal dimension, 0103 physical sciences, Surface roughness, Ryugu, comets, 010303 astronomy & astrophysics, Image resolution, 0105 earth and related environmental sciences, Physics, Micrometeoroid, in-situ observations, Planetengeodäsie, Astronomy and Astrophysics, Systementwicklung und Projektbüro, Roughness, Planetengeologie, Space and Planetary Science, Micrometeorite, Asteroid, Planetare Sensorsysteme
Abstract: Alteration processes on asteroid and comet surfaces, such as thermal fracturing, (micrometeorite) impacts or volatile outgassing, are complex mechanisms that form diverse surface morphologies and roughness on various scales. These mechanisms and their interaction may differ on the surfaces of different bodies. Asteroid Ryugu and comet 67P/Churyumov–Gerasimenko, both, have been visited by landers that imaged the surfaces in high spatial resolution. We investigate the surface morphology and roughness of Ryugu and 67P/Churyumov–Gerasimenko based on high-resolution in situ images of 0.2 and 0.8 mm pixel resolution over an approximately 25 and 80 cm wide scene, respectively. To maintain comparability and reproducibility, we introduce a method to extract surface roughness descriptors (fractal dimension, Hurst exponent, joint roughness coefficient, root-mean-square slope, hemispherical crater density, small-scale roughness parameter, and Hapke mean slope angle) from in situ planetary images illuminated by LEDs. We validate our method and choose adequate parameters for an analysis of the roughness of the surfaces. We also derive the roughness descriptors from 3D shape models of Ryugu and orbiter camera images and show that the higher spatially resolved images result in a higher roughness. We find that 67P/Churyumov–Gerasimenko is up to 6 per cent rougher than Ryugu depending on the descriptor used and attribute this difference to the different intrinsic properties of the materials imaged and the erosive processes altering them. On 67P/Churyumov–Gerasimenko sublimation appears to be the main cause for roughness, while on Ryugu micrometeoroid bombardment as well as thermal fatigue and solar weathering may play a significant role in shaping the surface.
Published: 2021

8. Bilobate comet morphology and internal structure controlled by shear deformation

Author: Carsten Güttler, F. Preusker, Dennis Bodewits, Alice Lucchetti, Philippe Lamy, J.-B. Vincent, H. U. Keller, D. Nébouy, Björn Davidsson, A. T. Auger, Matteo Massironi, Stefano Debei, Cecilia Tubiana, F. La Forgia, Stubbe F. Hviid, Hans Rickman, M. De Cecco, Luca Penasa, M. A. Barucci, L. M. Lara, Nilda Oklay, C. Matonti, Nicholas Attree, J. L. Bertaux, Olivier Groussin, Sophie Viseur, Monica Lazzarin, Maurizio Pajola, Imre Toth, Francesco Marzari, Ivano Bertini, R. Rodrigo, Jakob Deller, Sylvain Bouley, Sonia Fornasier, Holger Sierks, V. Da Deppo, J. J. Lopez-Moreno, Wing-Huen Ip, Laurent Jorda, Giampiero Naletto, G. Cremonese, Frank Scholten, Marco Fulle, Xian Shi, Stefano Mottola, P. J. Gutierrez, Detlef Koschny, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-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), Faculty of Natural Sciences [Stirling], University of Stirling, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-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), 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), Instituto de Astrofísica de Andalucía (IAA), 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), 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 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), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], Department of Physics and Astronomy [Uppsala], Uppsala University, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), national funding agency of Germany (DLR), national funding agency of France (CNES), national funding agency of Italy (ASI), national funding agency of Spain (MEC), national funding agency of Sweden (SNSB), ESA Technical Directorate, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), 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, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), European Space Agency (ESA)-European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, 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], Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), and 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)
Subjects: Solar System, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, 3d analysis, Comet, Geophysics, 010502 geochemistry & geophysics, 01 natural sciences, rosetta, Shear (geology), [SDU]Sciences of the Universe [physics], 13. Climate action, General Earth and Planetary Sciences, Sublimation (phase transition), Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Earth and Planetary Sciences (all), Geology, 0105 earth and related environmental sciences
Abstract: Bilobate comets—small icy bodies with two distinct lobes—are a common configuration among comets, but the factors shaping these bodies are largely unknown. Cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the Sun, but the importance of a comet’s internal structure on its erosion is unclear. Here we present three-dimensional analyses of images from the Rosetta mission to illuminate the process that shaped the Jupiter-family bilobate comet 67P/Churyumov–Gerasimenko over billions of years. We show that the comet’s surface and interior exhibit shear-fracture and fault networks, on spatial scales of tens to hundreds of metres. Fractures propagate up to 500 m below the surface through a mechanically homogeneous material. Through fracture network analysis and stress modelling, we show that shear deformation generates fracture networks that control mechanical surface erosion, particularly in the strongly marked neck trough of 67P/Churyumov–Gerasimenko, exposing its interior. We conclude that shear deformation shapes and structures the surface and interior of bilobate comets, particularly in the outer Solar System where water ice sublimation is negligible. The shape and internal structure of bilobate comet 67P is controlled by shear deformation inducing mechanically driven erosion along shear fracture networks, according to a 3D analysis of images from the Rosetta mission.
Published: 2019
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9. Compressive strength and elastic modulus at Agilkia on comet 67P/Churyumov-Gerasimenko derived from the SESAME/CASSE touchdown signals

Author: Alberto Flandes, K. Thiel, D. Möhlmann, Hans-Herbert Fischer, Frank Scholten, Martin Knapmeyer, Harald Krüger, Claudia Faber, R. Roll, Walter Arnold, and Klaus J. Seidensticker
Subjects: Asteroiden und Kometen, Materials science, 010504 meteorology & atmospheric sciences, Planetengeodäsie, Leitungsbereich PF, Touchdown, Astronomy and Astrophysics, Fracture mechanics, Mechanics, 01 natural sciences, Elasticity, Nutzerzentrum für Weltraumexperimente (MUSC), Depth sounding, Comet surface material, Compressive strength, Planetenphysik, Space and Planetary Science, Compression strength, 0103 physical sciences, Contact zone, Elasticity (economics), Porosity, 010303 astronomy & astrophysics, Elastic modulus, 0105 earth and related environmental sciences
Abstract: We report an analysis of the Comet Acoustic Surface Sounding Experiment (CASSE) acceleration signals at Philae's first touchdown site Agilkia on comet 67P/Churyumov-Gerasimenko. The signals yield the forces in the contact zone foot-sole and comet surface, and from these forces a compression strength of approximately 10 kPa can be derived. The sole's contact-resonances provide an elastic modulus of the order of 10 MPa. Our results are partially based on calibration experiments, which are described in the appendix of the current paper. Relations known in material science, linking porosity to elasticity and fracture energy, allow one to check the interdependence between compression strength and elasticity.
Published: 2018
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10. 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
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11. Long-term survival of surface water ice on comet 67P

Author: Alice Lucchetti, M. De Cecco, R. Rodrigo, Michael Küppers, Laurent Jorda, Ivano Bertini, Nilda Oklay, W-H. Ip, Detlef Koschny, Marc Hofmann, J. L. Bertaux, Frank Scholten, Nicolas Thomas, J.-R. Kramm, V. Da Deppo, Clement Feller, P. J. Gutierrez, Dennis Bodewits, Sonia Fornasier, Carsten Güttler, I. Hall, Maurizio Pajola, Nafiseh Masoumzadeh, Francesco Marzari, Marco Fulle, A. Gicquel, M. A. Barucci, Jörg Knollenberg, Holger Sierks, Cesare Barbieri, Monica Lazzarin, Jakob Deller, Zhong-Yi Lin, David Kappel, Olivier Groussin, J. J. Lopez Moreno, Jean-Baptiste Vincent, Horst Uwe Keller, Michael F. A'Hearn, Luisa Lara, Giampiero Naletto, Pedro Hasselmann, Björn Davidsson, Cecilia Tubiana, Philippe Lamy, Antoine Pommerol, Stubbe F. Hviid, Hans Rickman, Frank Preusker, Xian Shi, Stefano Mottola, Gábor L. Kovács, Gabriele Cremonese, Ekkehard Kührt, J. D. P. Deshapriya, Stefano Debei, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), NASA Ames Research Center (ARC), 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), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), 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), 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), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), 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), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, 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), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Infrared, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Narrow angle, Astrophysics, 01 natural sciences, Methods: data analysis, 0103 physical sciences, Long term survival, Techniques: imaging spectroscopy, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Leitungsbereich PF, Planetengeodäsie, Astronomy and Astrophysics, 620 Engineering, 13. Climate action, Space and Planetary Science, Water ice, Surface water
Abstract: Numerous water-ice-rich deposits surviving more than several months on comet 67P/Churyumov-Gerasimenko were observed during the Rosetta mission. We announce the first-time detection of water-ice features surviving up to 2 yr since their first observation via OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) NAC (narrow angle camera). Their existence on the nucleus of comet 67P at the arrival of the Rosetta spacecraft suggests that they were exposed to the surface during the comet's previous orbit. We investigated the temporal variation of large water-ice patches to understand the long-term sustainability of water ice on cometary nuclei on time-scales of months and years. Large clusters are stable over typical periods of 0.5 yr and reduce their size significantly around the comet's perihelion passage, while small exposures disappear. We characterized the temporal variation of their multispectral signatures. In large clusters, dust jets were detected, whereas in large isolated ones no associated activity was detected. Our thermal analysis shows that the long-term sustainability of water-ice-rich features can be explained by the scarce energy input available at their locations over the first half year. However, the situation reverses for the period lasting several months around perihelion passage. Our two end-member mixing analysis estimates a pure water-ice equivalent thickness up to 15 cm within one isolated patch, and up to 2 m for the one still observable through the end of the mission. Our spectral modelling estimates up to 48 per cent water-ice content for one of the large isolated feature, and up to 25 per cent water ice on the large boulders located within clusters.
Published: 2017
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12. Magnetic Properties of Asteroid (162173) Ryugu

Author: Christian Krause, Frank Scholten, Jürgen Blum, Carsten Güttler, D. Constantinescu, Andreas Hördt, Kaname Sasaki, Karl-Heinz Glassmeier, Benjamin P. Weiss, Hans-Ulrich Auster, Laurence Lorda, Uwe Motschmann, Masaki Fujimoto, Tra-Mi Ho, J. T. Grundmann, Ayako Matsuoka, Olaf Hillenmaier, Kathrin Gebauer, Ekkehard Kührt, Aurelie Moussi-Soffys, Karl-Heinz Fornacon, David Hercik, Ingo Richter, B. Stoll, and Friederike Wolff
Subjects: Asteroiden und Kometen, asteroids, asteroid, MASCOT, Planetengeodäsie, Astronomy, Systementwicklung und Projektbüro, magnetic field, magnetization, Magnetic field, Magnetization, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Asteroid, Hayabusa2 mission, Earth and Planetary Sciences (miscellaneous), Planetare Sensorsysteme, Ryugu, magnetic properties, Mechanik und Thermalsysteme, Institut für Optische Sensorsysteme, Geology, Hayabusa2
Abstract: Observations of the magnetization state of asteroids indicate diverse properties. Values between 1.9 × 10 −6 Am 2/kg (Eros) and 10 −2 Am 2/kg (Braille) have been reported. A more detailed understanding of asteroidal magnetic properties allows far-reaching conclusions of the magnetization mechanism as well as the strength of the magnetic field of the solar system regions the asteroid formed in. The Hayabusa2 mission with its lander Mobile Asteroid Surface Scout is equipped with a magnetometer experiment, MasMag. MasMag is a state-of-the-art three-axis fluxgate magnetometer, successfully operated also on Philae, the Rosetta mission lander. MasMag has enabled, after Eros for the second time ever, to determine the magnetic field of an asteroid during descent and on-surface operations. The new observations show that Ryugu, a low-albedo C-type asteroid, has no detectable global magnetization, and any local magnetization is either small (
Published: 2020

13. 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
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14. Spectrophotometric Analysis of the Ryugu Rock Seen by MASCOT: Searching for a Carbonaceous Chondrite Analog

Author: Tra-Mi Ho, R. Jaumann, Alexander Koncz, Frank Trauthan, Katharina A. Otto, Nicole Schmitz, Harald Michaelis, Hannah Scharf, Stefan Schröder, Frank Scholten, Klaus-Dieter Matz, Stefano Mottola, Hikaru Yabuta, and Seiji Sugita
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Phase angle, FOS: Physical sciences, Mineralogy, Astronomy and Astrophysics, Spectrophotometry Ryugu MASCOT Carbonaceous Chondrite Analog Asteroid, Matrix (geology), Geophysics, Meteorite, Space and Planetary Science, Asteroid, Chondrite, Absorption band, Carbonaceous chondrite, Spectral slope, Earth and Planetary Sciences (miscellaneous), Astrophysics - Earth and Planetary Astrophysics
Abstract: We analyze images of a rock on Ryugu acquired in situ by MASCam, the camera on the mascot lander, with the aim of identifying possible carbonaceous chondrite (CC) analogs. The rock’s reflectance ( r F = 0.034 ± 0.003 at phase angle 4.5 ∘ ± 0.1 ∘ ) is consistent with Ryugu’s average reflectance, suggesting that the rock is typical for this asteroid. A spectrophotometric analysis of the rock’s inclusions provides clues to its CC group membership. Inclusions are generally brighter than the matrix. The dominant variation in their color is a change in the visible spectral slope, with many inclusions being either red or blue. Spectral variation in the red channel hints at the presence of the 0.7 μm absorption band linked to hydrated phyllosilicates. The inclusions are unusually large for a CC; we find that their size distribution may best match that of the Renazzo (CR2) and Leoville (CV3) meteorites. The Ryugu rock does not easily fit into any of the CC groups, consistent with the idea that typical Ryugu-type meteorites are too fragile to survive atmospheric entry.
Published: 2021
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15. Constraining models of activity on comet 67P/Churyumov-Gerasimenko with Rosetta trajectory, rotation, and water production measurements

Author: Paul Hartogh, J. Knollenberg, Olivier Groussin, Nicolas Thomas, Yann Brouet, Laurent Jorda, Frank Preusker, Frank Scholten, S. F. Hviid, Rafael Rodrigo, Nicholas Attree, Stefano Mottola, Martin Knapmeyer, E. Kührt, 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Medical Genetics, Heath Park, Cardiff, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Deutsches Zentrum für Luft- und Raumfahrt (DLR), 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), Universität Bern [Bern], Max Planck Institute for Solar System Research (MPS), 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: 010504 meteorology & atmospheric sciences, planets and satellites: dynamical evolution and stability, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Rotation, 01 natural sciences, planets and satellites: dynamical evolution and stability – comets: individual: 67P/Churyumov-Gerasimenko - comets: general, Acceleration, Orientation (geometry), 0103 physical sciences, Range (statistics), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 520 Astronomy, comets: general, Momentum transfer, Astronomy and Astrophysics, Flight dynamics (fixed-wing aircraft), comets: individual (Churyumov-Gerasimenko), 620 Engineering, 13. Climate action, Space and Planetary Science, Trajectory, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We use four observational data sets, mainly from the Rosetta mission, to constrain the activity pattern of the nucleus of comet 67P/Churyumov-Gerasimenko. Methods. We develop a numerical model that computes the production rate and non-gravitational acceleration of the nucleus of comet 67P as a function of time, taking into account its complex shape with a shape model reconstructed from OSIRIS imagery. We use this model to fit three observational data sets: the trajectory data from flight dynamics; the rotation state, as reconstructed from OSIRIS imagery; and the water production measurements from ROSINA, of 67P. The two key parameters of our model, adjusted to fit the three data sets all together, are the activity pattern and the momentum transfer efficiency (i.e., the so-called "$\eta$ parameter" of the non-gravitational forces). Results. We find an activity pattern able to successfully reproduce the three data sets simultaneously. The fitted activity pattern exhibits two main features: a higher effective active fraction in two southern super-regions ($\sim 10$~\%) outside perihelion compared to the northern ones ($< 4$~\%), and a drastic rise of the effective active fraction of the southern regions ($\sim 25-35$~\%) around perihelion. We interpret the time-varying southern effective active fraction by cyclic formation and removal of a dust mantle in these regions. Our analysis supports moderate values of the momentum transfer coefficient $\eta$ in the range $0.6-0.7$; values $\eta\leq0.5$ or $\eta\geq0.8$ degrade significantly the fit to the three data sets. Our conclusions reinforce the idea that seasonal effects linked to the orientation of the spin axis play a key role in the formation and evolution of dust mantles, and in turn largely control the temporal variations of the gas flux., Comment: 12 pages, 17 figures. Accepted for publication in forthcoming Rosetta issue of Astronomy and Astrophysics
Published: 2019
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16. A comparison of multiple Rosetta data sets and 3D model calculations of 67P/Churyumov-Gerasimenko coma around equinox (May 2015)

Author: F. Preusker, Ladislav Rezac, Laurent Jorda, Martin Rubin, P. Theologou, Jong-Shinn Wu, O. Pinzón-Rodríguez, Kathrin Altwegg, Clémence Herny, David Marshall, S. K. Dadzie, Nicolas Thomas, Selina-Barbara Gerig, Stefano Mottola, David Kappel, C. C. Su, Ekkehard Kührt, Chariton Christou, Gabriele Arnold, Y. Liao, Raphael Marschall, Paul Hartogh, Rafael Rodrigo, Frank Scholten, Olivier Groussin, O. Mousis, Laboratoire d'Astrophysique de Marseille (LAM), and 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)
Subjects: 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, 530 Physics, Comet, 3d model, Equinox, Astrophysics, 01 natural sciences, 0103 physical sciences, Rosetta, Comets, Coma, DSMC, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Spacecraft, biology, business.industry, 520 Astronomy, Leitungsbereich PF, Planetengeodäsie, Comet 67P, Astronomy and Astrophysics, Dust, biology.organism_classification, 620 Engineering, Dynamics, Outgassing, Comets 67P/Churyumov-Gerasimenko Coma Dust Dynamics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Bulk velocity, Osiris, business
Abstract: International audience; We have used the latest available shape model for gas and dust simulations of the inner coma of comet 67P/Churyumov-Gerasimenko for the period around May 2015 (equinox). We compare results from a purely insolation-driven model with a complementary set of observations made by ROSINA, VIRTIS, MIRO, and OSIRIS within the same period. The observations include - for the first time - inverted MIRO measurements of gas density, temperature and bulk velocity to constrain the model. The comparisons show that, as in November 2014 (Marschall et al., 2016), insolation-driven activity does not provide an adequate fit to the data. Both VIRTIS and MIRO observations indicate that emissions from the Hatmehit and Imhotep regions of the nucleus are strongly depleted in total gas, H2O, and dust emissions in this case. The MIRO inversion provides a challenging constraint to the models as a consequence of the terminator orbit and nucleus pointing of the spacecraft. Nonetheless a consistent picture with a dominance of outgassing from the Hapi region, even at equinox, is clearly evident. An inhomogeneous model consistent with models proposed for the November 2014 time-frame was constructed and provides a better fit to the data. As far as we are aware this is the first time comae data from four Rosetta instruments have been used to constrain within one self-contained model the emission distribution at the nucleus surface and study the dynamics of the gas and dust outflow.
Published: 2019
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17. The Hayabusa2 lander MASCOT on the surface of Asteroid (162173) Ryugu -- Stereo-photogrammetric analysis of MASCam image data

Author: Frank Scholten, Seiji Sugita, Ralf Jaumann, Stefan Schröder, Tra-Mi Ho, Klaus-Dieter Matz, Frank Trauthan, Nicole Schmitz, Stephan Elgner, A. Koncz, Shingo Kameda, F. Preusker, Jens Biele, Matthias Grott, and Maximilian Hamm
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, data analysis, Field of view, Astrophysics, 01 natural sciences, Mascot, Planetenphysik, 0103 physical sciences, Computer vision, Ryugu, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Rest (physics), Physics, asteroid, Pixel, business.industry, Orientation (computer vision), MASCOT, Planetengeodäsie, Astronomy and Astrophysics, Systementwicklung und Projektbüro, MASCam, image processing, Nutzerzentrum für Weltraumexperimente (MUSC), Planetengeologie, Photogrammetry, Space and Planetary Science, Asteroid, Planetare Sensorsysteme, Artificial intelligence, business
Abstract: After its release and a descent and bouncing phase, the Hayabusa2 lander MASCOT came to a final rest and MASCOT’s camera MASCam acquired a set of images of the surface of Ryugu. With MASCam’s instantaneous field of view of about 1 mrad, the images provide pixel scales from 0.2 to 0.5 mm pixel−1in the foreground and up to 1 cm pixel−1for surface parts in the background. Using a stereo-photogrammetric analysis of the MASCam images taken from slightly different positions due to commanded and unintentional movements of the MASCOT lander, we were able to determine the orientation for the different measurement positions. Furthermore, we derived a 3D surface model of MASCOT’s vicinity. Although the conditions for 3D stereo processing were poor due to very small stereo angles, the derived 3D model has about 0.5 cm accuracy in the foreground at 20 cm distance and about 1.5 cm at a distance of 40–50 cm.
Published: 2019
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18. 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
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19. 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
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20. The MASCOT landing area on Asteroid (162173) Ryugu: Stereo-photogrammetric analysis using images of the ONC onboard the Hayabusa2 spacecraft

Author: Klaus-Dieter Matz, Manabu Yamada, Stephan Elgner, Tomokatsu Morota, Ralf Jaumann, Yuichiro Cho, Frank Scholten, Seiji Sugita, Masahiko Hayakawa, Yasuhiro Yokota, Shingo Kameda, F. Preusker, Kazunori Ogawa, Rie Honda, Hidehiko Suzuki, Kosuke Yoshioka, Eri Tatsumi, T. Roatsch, C. Honda, H. Sawada, Toru Kouyama, Naoya Sakatani, and Moe Matsuoka
Subjects: (162173) Ryugu, 010504 meteorology & atmospheric sciences, landing site, Context (language use), Astrophysics, 01 natural sciences, Mascot, 0103 physical sciences, Digital elevation model, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Block (data storage), Physics, Radiometer, Spacecraft, business.industry, Asteroid, MASCOT, Astronomy and Astrophysics, Photogrammetry, Space and Planetary Science, stereo-photogrammetry, trajectory, business, Hayabusa2
Abstract: A high-resolution 3D surface model, map-projected to a digital terrain model (DTM), and precisely ortho-rectified context images (orthoimages) of MASCOT landing site area are important data sets for the scientific analysis of relevant data that have been acquired with MASCOT’s image camera system MASCam and other instruments (e.g., the radiometer MARA and the magnetometer MASMag). We performed a stereo-photogrammetric (SPG) analysis of 1050 images acquired from the Hayabusa2 Optical Navigation Camera system (ONC) during the asteroid characterization phase and the MASCOT release phase in early October 2018 to construct a photogrammetric control point network of asteroid (162173) Ryugu. We validated existing rotational parameters for Ryugu and improved the camera orientation (position and pointing) of the ONC images to decimeter accuracy using SPG bundle block adjustment. We produced a high-resolution DTM of the entire MASCOT landing site area. Finally, based on this DTM, a set of orthoimages from the highest-resolution ONC images around MASCOT’s final rest position complements the results of this analysis.
Published: 2019

21. The descent and bouncing path of the Hayabusa2 lander MASCOTat asteroid (162173) Ryugu

Author: Kosuke Yoshioka, Hidehiko Suzuki, Christian Grimm, Kazunori Ogawa, Yuichiro Cho, Moe Matsuoka, Nicole Schmitz, Yasuhiro Yokota, Stephan Elgner, Rie Honda, K-D Matz, C. Honda, Naoya Sakatani, Frank Trauthan, Manabu Yamada, H. Sawada, Seiji Sugita, Frank Scholten, Maximilian Hamm, Matthias Grott, Tomokatsu Morota, Shingo Kameda, Eri Tatsumi, Frank Preusker, Alexander Koncz, Toru Kouyama, Ralf Jaumann, Jens Biele, David Hercik, Masahiko Hayakawa, Tra-Mi Ho, and H. U. Auster
Subjects: 010504 meteorology & atmospheric sciences, data analysis, Astrophysics, 01 natural sciences, Mascot, Planetenphysik, Position (vector), 0103 physical sciences, Shadow, Point (geometry), Ryugu, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Rest (physics), Physics, asteroid, Spacecraft, business.industry, MASCOT, Planetengeodäsie, Astronomy and Astrophysics, Systementwicklung und Projektbüro, Geodesy, Nutzerzentrum für Weltraumexperimente (MUSC), image processing, Planetengeologie, Space and Planetary Science, Asteroid, Land und Explorationstechnologie, Planetare Sensorsysteme, Descent (aeronautics), business
Abstract: Images from the Optical Navigation Camera system (ONC) onboard the Hayabusa2 spacecraft show the MASCOT lander during its descent to the surface of asteroid (162173) Ryugu. We used results from a previous stereo-photogrammetric analysis that provided precise ONC image orientation data (camera position and pointing), ONC orthoimages, and an ONC-based 3D surface model to combine them with the visibilities of MASCOT itself and its shadow on-ground within the ONC images. We integrated additional information from instruments onboard MASCOT (MASMag, MARA, MASCam) and derived MASCOT’s release position and modeled its free-fall descent path and its velocity over 350 s from its release at ∼41 m altitude above ground until its first contact with the surface of Ryugu. After first contact, MASCOT bounced over the surface of Ryugu for 663 s and came to rest at its first settlement point after four intermediate surface contacts. We again used ONC images that show MASCOT and partly its shadow and reconstructed the bouncing path and the respective velocities of MASCOT. The achieved accuracy for the entire descent and bouncing path is ∼0.1 m (1σ).
Published: 2019

22. Variegation and space weathering on asteroid 21 Lutetia

Author: Stefan Schröder, Frank Preusker, Frank Scholten, Klaus-Dieter Matz, Horst Uwe Keller, Stubbe F. Hviid, and Stefano Mottola
Subjects: Asteroiden und Kometen, Earth and Planetary Astrophysics (astro-ph.EP), Planetengeodäsie, FOS: Physical sciences, Color analysis, Astronomy, Astronomy and Astrophysics, Space weathering, Regolith, Asteroid Lutetia, Planetengeologie, Impact crater, Spectrophotometry, Space and Planetary Science, Asteroid, Variegation (histology), Opposition effect, High spatial resolution, Variation (astronomy), Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: During the flyby in 2010, the OSIRIS camera on-board Rosetta acquired hundreds of high-resolution images of asteroid Lutetia's surface through a range of narrow-band filters. While Lutetia appears very bland in the visible wavelength range, Magrin et al. (2012) tentatively identified UV color variations in the Baetica cluster, a group of relatively young craters close to the north pole. As Lutetia remains a poorly understood asteroid, such color variations may provide clues to the nature of its surface. We take the color analysis one step further. First we orthorectify the images using a shape model and improved camera pointing, then apply a variety of techniques (photometric correction, principal component analysis) to the resulting color cubes. We characterize variegation in the Baetica crater cluster at high spatial resolution, identifying crater rays and small, fresh impact craters. We argue that at least some of the color variation is due to space weathering, which makes Lutetia's regolith redder and brighter.
Published: 2015
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23. Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

Author: H. U. Keller, Carsten Güttler, M. A. Barucci, Ivano Bertini, A. T. Auger, Matteo Massironi, M. De Cecco, Simone Marchi, Stubbe F. Hviid, Raphael Marschall, Mohamed Ramy El-Maarry, Frank Scholten, Maurizio Pajola, Cesare Barbieri, Hans Rickman, R. Rodrigo, Jörg Knollenberg, Stefano Mottola, Jakob Deller, Marco Fulle, Michael Küppers, A. Gracia-Berná, Nilda Oklay, W-H. Ip, V. Da Deppo, P. J. Gutiérrez, Laurent Jorda, Holger Sierks, Sonia Fornasier, Jean-Loup Bertaux, J.-B. Vincent, Harald Michalik, Olivier Groussin, Antoine Pommerol, Marc Hofmann, Frank Preusker, Detlef Koschny, Nicolas Thomas, J.-R. Kramm, Monica Lazzarin, B. J. R. Davidsson, Philippe Lamy, Ekkehard Kührt, Cecilia Tubiana, L. M. Lara, Francesco Marzari, J. J. Lopez Moreno, Michael F. A'Hearn, Gabriele Cremonese, Stefano Debei, S. Höfner, Géza Kovács, and Giampiero Naletto
Subjects: Insolation, Physics, 010504 meteorology & atmospheric sciences, biology, Comet, Diurnal temperature variation, Weathering, Geophysics, biology.organism_classification, 01 natural sciences, Thermal contraction, Astrobiology, 13. Climate action, 0103 physical sciences, General Earth and Planetary Sciences, Osiris, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.
Published: 2015
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24. On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

Author: Olivier Groussin, Björn Davidsson, Giampiero Naletto, S. Fornasier, Cecilia Tubiana, Horst Uwe Keller, P. L. Lamy, Michael Küppers, J.F. Wu, Hans Rickman, M. A. Barucci, W-H. Ip, Ekkehard Kührt, Stubbe F. Hviid, Selina-Barbara Gerig, L. M. Lara, C. C. Su, Marco Fulle, Nilda Oklay, R. Rodrigo, Monica Lazzarin, Stefano Mottola, Jean-Baptiste Vincent, V. Da Deppo, Laurent Jorda, Jörg Knollenberg, P. J. Gutierrez, Stefano Debei, Frank Scholten, G. Cremonese, M. De Cecco, Holger Sierks, Frank Preusker, J. L. Bertaux, Cesare Barbieri, Jakob Deller, Raphael Marschall, Dennis Bodewits, J. J. Lopez Moreno, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Carsten Güttler, Jessica Agarwal, Imre Tóth, Francesco Marzari, J.-R. Kramm, Swiss National Science Foundation, European Commission, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), 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], 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), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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), 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), 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, 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), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern], Institute of Space Science [Taiwan], Max-Planck-Institut für Sonnensystemforschung (MPS), Max Planck Institute for Solar System Research (MPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), University of Bern (UBERN), International Space Science Institute (ISSI), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Department of Astronomy, University of Maryland, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF - Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy, Graduate Institute of Astronomy, Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Science Operations Department, European Space Astronomy Centre/ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics, National Tsing Hua University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany, Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy, 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), European Space Agency (ESA), Space Research Center, Polish Academy of Sciences (Warsaw), Observatoire de Paris, Université Paris sciences et lettres (PSL), CNR-IFN UOS Padova LUXOR, Università di Trento (UNITN), Instituto de Astrofisica de Andalucia, CSIC (IAA), Dipartimento di Fisica, Università di Padova, Universita degli Studi di Padova, California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-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), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Technische Universität Braunschweig [Braunschweig], 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), 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), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Infrared, 67P/Churyumov–Gerasimenko, Astrophysics, Dust, Inner coma, OSIRIS, Rosetta, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Particle acceleration, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Test particle, Impact parameter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: 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. For commercial reuse, permission must be requested below., The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma. In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/b+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database. Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow. A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis. As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given. © 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. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.
Published: 2018
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25. 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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26. The high resolution stereo camera (HRSC): acquisition of multi-spectral 3D-data and photogrammetric processing

Author: Frank Scholten, Gerhard Neukum, Klaus Gwinner, and Ralf Jaumann
Subjects: Multispectral data, Orientation (computer vision), business.industry, Multispectral image, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Multi spectral, Geography, Photogrammetry, Global Positioning System, Computer vision, Artificial intelligence, business, High Resolution Stereo Camera, Remote sensing, Camera control
Abstract: At the Institute of Space Sensor Technology and Planetary Exploration of the German Aerospace Center (DLR) the High Resolution Stereo Camera (HRSC) has been designed for international missions to planet Mars. For more than three years an airborne version of this camera, the HRSC-A, has been successfully applied in many flight campaigns and in a variety of different applications. It combines 3D-capabilities and high resolution with multispectral data acquisition. Variable resolutions depending on the camera control settings can be generated. A high-end GPS/INS system in combination with the multi-angle image information yields precise and high-frequent orientation data for the acquired image lines. In order to handle these data a completely automated photogrammetric processing system has been developed, and allows to generate multispectral 3D-image products for large areas and with accuracies for planimetry and height in the decimeter range. This accuracy has been confirmed by detailed investigations.
Published: 2017
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27. 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
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28. Seasonal Mass Transfer on the Nucleus of Comet 67P/Chuyumov-Gerasimenko

Author: Frank Preusker, Wing-Huen Ip, Laurent Jorda, J. J. López-Moreno, Carsten Güttler, H. Rickman, Michael Küppers, Stubbe F. Hviid, Holger Sierks, Katharina A. Otto, G. Cremonese, M. A. Barucci, J. Deller, Ivano Bertini, Nilda Oklay, P. J. Gutierrez, Michael F. A'Hearn, Marc Hofmann, Nicolas Thomas, Frank Scholten, Jessica Agarwal, P. L. Lamy, Maurizio Pajola, V. Da Deppo, M. De Cecco, J.-R. Kramm, Cecilia Tubiana, Francesco Marzari, Imre Toth, Marco Fulle, Cesare Barbieri, Xian Shi, Stefano Mottola, Yuri V. Skorov, B. J. R. Davidsson, J. L. Bertaux, D. Koschny, Giampiero Naletto, Stefan Schröder, Monica Lazzarin, Dennis Bodewits, Jean-Baptiste Vincent, Sonia Fornasier, H. U. Keller, Jörg Knollenberg, Rafael Rodrigo, Ekkehard Kührt, L. M. Lara, Olivier Groussin, Stefano Debei, 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], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Uppsala], Uppsala University, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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), Consejo Superior de Investigaciones Científicas [Madrid] (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 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), 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 Trieste (OAT), 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], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], 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), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Universität Bern [Bern] (UNIBE), and ITA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets: individual (67P/Churyumov-Gerasimenko), Methods: data analysis, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Radiation, Granular material, 01 natural sciences, comet, Mass transfer, individual 67P/Churyumov-Gerasimenko, 0103 physical sciences, medicine, Comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 620 Engineering, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Water vapor, Astrophysics - Earth and Planetary Astrophysics
Abstract: We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material that indicates back fall originating from the active south. Decimetre sized chunks contain water ice and their trajectories are influenced by an anti-solar force instigated by sublimation. OSIRIS observations suggest that up to 20 % of the particles directly return to the nucleus surface taking several hours of travel time. The back fall covered northern areas are active if illuminated but produce mainly water vapour. The decimetre chunks from the nucleus surface are too small to contain more volatile compounds such as CO 2 or CO. This causes a north-south dichotomy of the composition measurements in the coma. Active particles are trapped in the gravitational minimum of Hapi during northern winter. They are "shock frozen" and only reactivated when the comet approaches the sun after its aphelion passage. The insolation of the big cavity is enhanced by self-heating, i. e. reflection and IR radiation from the walls. This, together with the pristinity of the active back fall, explains the early observed activity of the Hapi region. Sobek may be a role model for the consolidated bottom of Hapi. Mass transfer in the case of 67P strongly influences the evolution of the nucleus and the interpretation of coma measurements., Comment: 17 pages, 20 figures
Published: 2017
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29. Rosetta Lander - Philae: Operations on comet 67P/Churyumov-Gerasimenko, analysis of wake-up and final state

Author: Sylvain Lodiot, B. Grieger, Jörg Knollenberg, Koen Geurts, Frank Scholten, Laurence O'Rourke, Valentina Lommatsch, Oliver Küchemann, Pablo Muñoz, Stephan Ulamec, Antoine Charpentier, Eric Jurado, Ekkehard Kührt, Stefano Mottola, Rafael Andres, Martin Knapmeyer, Thierry Martin, Cinzia Fantinati, Cedric Delmas, Romain Garmier, Michael Maibaum, and Jens Biele
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Engineering, 010504 meteorology & atmospheric sciences, Comet, Aerospace Engineering, 01 natural sciences, law.invention, Orbiter, Aeronautics, Planetenphysik, law, 0103 physical sciences, 010303 astronomy & astrophysics, Rosetta Lander, 0105 earth and related environmental sciences, biology, Payload, business.industry, Member states, Planetengeodäsie, biology.organism_classification, Philae, Nutzerzentrum für Weltraumexperimente (MUSC), On board, Osiris, business
Abstract: The Lander Philae, part of the ESA Rosetta mission successfully landed on comet 67P/Churyumov- Gerasimenko on November 12th, 2014. After several (unplanned) bounces it performed a First Scientific Sequence (FSS), based on the energy stored in its on board batteries. All ten instruments of the payload aboard Philae have been operated at least once. Due to the fact that the final landing site was poorly illuminated, Philae went into hibernation on November 15th. Signals from the Lander were received again in June and July 2015, which indicated multiple awakening episodes of the lander. However, various attempts to re-establish reliable and stable communications links failed. Based on the analysis of the data gained during FSS, and during the contacts in June and July 2015 we draw conclusions on the state of Philae. In addition, images from the OSIRIS camera aboard the Rosetta Orbiter have allowed the identification of the exact position of Philae and its attitude, relative to the local surface terrain. This paper also gives an overview of the implications of Philae results for future engineering comet models, required particularly for the design of in-situ (landing) or sample return missions. 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 with additional contributions from Hungary, UK, Finland, Ireland and Austria.
Published: 2017

30. 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
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31. Illumination conditions at the lunar south pole using high resolution Digital Terrain Models from LOLA

Author: P. Gläser, Frank Scholten, Gregory A. Neumann, Jürgen Oberst, D. De Rosa, Mark S. Robinson, Erwan Mazarico, and R. Marco Figuera
Subjects: Sunlight, Landing Sites, geography, geography.geographical_feature_category, Pixel, Astronomy and Astrophysics, Terrain, Laser, law.invention, Surface, Impact crater, Space and Planetary Science, law, Ridge, Altimeter, Moon, Digital elevation model, Geology, Remote sensing
Abstract: The illumination conditions of the lunar south pole are investigated using a geometrically adjusted, 20 m/pixel Digital Terrain Model (DTM) from laser tracks of the Lunar Orbiter Laser Altimeter (LOLA). Several comparisons with Narrow Angle Camera (NAC) images have been made to cross-validate the results. Illumination conditions were first evaluated over a region of 20 × 20 km over a one-year period (October 22, 2018 – October 22, 2019) at surface level and 2 m above ground. Three potential landing sites are investigated in more detail. A 19-year study covering the lunar precessional cycle was carried out at surface level, 2 and 10 m above ground for a site found at “Connecting Ridge”, the ridge connecting the Shackleton and de Gerlache crater. This area was found to be an ideal site for future landing missions with respect to illumination conditions. We identified locations receiving sunlight for 92.27% of the time at 2 m above ground and 95.65% of the time at 10 m above ground. At these locations the longest continuous periods in darkness are typically only 3–5 days.
Published: 2014
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32. A homogeneous nucleus for comet 67P/Churyumov–Gerasimenko from its gravity field

Author: Laurent Jorda, Frank Scholten, Bernd Häusler, Kerstin Peter, Silvia Tellmann, Jean-Pierre Barriot, Tom Andert, Eberhard Grün, Matthias Hahn, Robert Gaskell, Sami W. Asmar, Holger Sierks, Michael K. Bird, P. R. Weissman, Martin Pätzold, Frank Preusker, Universität zu Köln, Institut für Raumfahrttechnik, Universität der Bundeswehr München [Neubiberg], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Rhenish Institute for Environmental Research (RIU), University of Cologne, Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Max-Planck-Institut für Sonnensystemforschung (MPS), 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Universität zu Köln = University of Cologne, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and 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)
Subjects: Physics, 67P, Multidisciplinary, 010504 meteorology & atmospheric sciences, nucleus, Comet, Astrophysics, 01 natural sciences, 7. Clean energy, Bulk density, gravity, Gravitation, comet, medicine.anatomical_structure, Volume (thermodynamics), Gravitational field, 13. Climate action, Asteroid, 0103 physical sciences, medicine, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Porosity, 010303 astronomy & astrophysics, Nucleus, 0105 earth and related environmental sciences
Abstract: International audience; Cometary nuclei consist mostly of dust and water ice(1). Previous observations have found nuclei to be low-density and highly porous bodies(2-4), but have only moderately constrained the range of allowed densities because of the measurement uncertainties. Here we report the precise mass, bulk density, porosity and internal structure of the nucleus of comet 67P/Churyumov-Gerasimenko on the basis of its gravity field. The mass and gravity field are derived from measured spacecraft velocity perturbations at fly-by distances between 10 and 100 kilometres. The gravitational point mass is GM = 666.2 +/- 0.2 cubic metres per second squared, giving a mass M = (9,982 +/- 3) x 10(9) kilograms. Together with the current estimate of the volume of the nucleus(5), the average bulk density of the nucleus is 533 +/- 6 kilograms per cubic metre. The nucleus appears to be a low-density, highly porous (72-74 per cent) dusty body, similar to that of comet 9P/Tempel 1(2,3). The most likely composition mix has approximately four times more dust than ice by mass and two times more dust than ice by volume. We conclude that the interior of the nucleus is homogeneous and constant in density on a global scale without large voids. The high porosity seems to be an inherent property of the nucleus material.
Published: 2016
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33. Mass-wasting features and processes in Vesta's south polar basin Rheasilvia

Author: Katrin Stephan, Klaus-Dieter Matz, Thomas Roatsch, Ralf Jaumann, Frank Scholten, Christopher T. Russell, Katharina A. Otto, Katrin Krohn, Frank Preusker, Paul M. Schenk, and Carol A. Raymond
Subjects: Landslide, Mass wasting, Structural basin, Granular material, Complex crater, Geophysics, Impact crater, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Digital elevation model, Geomorphology, Geology, Slumping
Abstract: [1] The Rheasilvia crater is Vesta's largest impact basin. It is a 500 km diameter complex crater centered near the south pole and overlying the 400 km diameter impact basin Veneneia. Using Framing Camera (FC) data from the Dawn spacecraft's Low Altitude Mapping Orbit (20 m/pixel) and a digital terrain model derived from High Altitude Mapping Orbit stereo data, we identified various mass-wasting features within the south polar region. These features include intra-crater mass movements, flow-like and creep-like structures, slumping areas, landslides, and curved radial and concentric ridges. Intra-crater mass-wasting features are represented by lobate slides, talus material, dark patches on the crater wall, spurs along the crater rim and boulders. Slumping areas develop in compact material, whereas landslides form in relatively loose material. Both may be triggered by seismic shaking induced by impacts. Intra-crater mass wasting and slid and slumped materials are homogeneously distributed throughout the basin. Slumping and sliding processes have contributed most efficiently to basin degradation. Flow-like and creep-like features originate from granular material and cluster between 0°E and 90°E, an area exposing shocked and fractured material from the Rheasilvia impact event. The radial curved ridges are likely to be remnants of the early Rheasilvia collapse process, when radially moving masses were deflected by the Coriolis Effect. The concentric ridges are artifacts from the crater rim collapse. Curved ridges at the intersection of Rheasilvia and Veneneia, and on Rheasilvia's central peak, may also have been influenced by the Rheasilvia basin relaxation process, and an oblique impact, respectively.
Published: 2013
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34. Cartography of the Lunokhod-1 landing site and traverse from LRO image and stereo-topographic data

Author: А. Konopikhin, Frank Scholten, I. Haase, Juergen Oberst, Irina Karachevtseva, O. Peters, E. Gusakova, Jeffrey B. Plescia, K. Shingareva, Mark S. Robinson, and E. Cherepanova
Subjects: Traverse, Pixel, Panorama, Spacecraft, business.industry, Orthophoto, Astronomy and Astrophysics, law.invention, Image (mathematics), Orbiter, Space and Planetary Science, law, Scale (map), business, Geology, Remote sensing
Abstract: We have derived a stereo-topographic model and an orthoimage mosaic based on Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images to study the Luna-17 landing site. In the images (0.33–0.5 m/pixel), the Lunokhod-1, the Luna-17 landed spacecraft, and the rover tracks can clearly be identified and mapped for 99% of the traverse. The traverse was found to be 9.93 km long, approximately 0.50 km shorter over what had been estimated earlier (10.54 km). The total topographic relief along the traverse was found to be within 26 m. Along its traverse, the rover encountered slopes of up to 5°, estimated over 2.5 m baselength. By comparison with previously published topographic maps and using our orthomosaic as a reference (which had been tied to the well-known Lunokhod-1 Laser reflector coordinates), we report on coordinates of Lunokhod-1's panorama points and overnight stops. Comparisons of currently mapped tracks with previous traverse reconstructions show good matches on small scale, but reveal that previous maps had long-wavelength geometric distortions of up to 100-m level. Agreement in topographic trends was very limited.
Published: 2013
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35. Geomorphological and spectrophotometric analysis of Seth's circular niches on comet 67P/Churyumov–Gerasimenko using OSIRIS images

Author: Monica Lazzarin, M. F. A'Hearn, Björn Davidsson, Cecilia Tubiana, Marco Fulle, Olivier Groussin, Frank Scholten, J.-B. Vincent, Sabrina Ferrari, Ekkehard Kührt, Xian Shi, Horst Uwe Keller, Stefano Mottola, L. M. Lara, Ivano Bertini, Michael Küppers, P. J. Gutierrez, Steve Boudreault, R. Rodrigo, Alice Lucchetti, Carsten Güttler, L. Z. Lin, F. La Forgia, Cesare Barbieri, Nilda Oklay, Jakob Deller, Holger Sierks, Sonia Fornasier, Detlef Koschny, Nicolas Thomas, V. Da Deppo, Maurizio Pajola, Clement Feller, Wing-Huen Ip, Laurent Jorda, M. Hoffman, Giampiero Naletto, Pedro Hasselmann, Jörg Knollenberg, J.-R. Kramm, Luca Penasa, G. Cremonese, Stefano Debei, M. De Cecco, J. L. Bertaux, J. J. Lopez Moreno, Philippe Lamy, M. A. Barucci, Matteo Massironi, Stubbe F. Hviid, Jessica Agarwal, Francesco Marzari, Hans Rickman, Frank Preusker, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), 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), Dipartimento di Geoscienze [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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), Agence Spatiale Européenne = European Space Agency (ESA), 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, 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), 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), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, 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), Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, comets: general-comets, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Terrain, 67P/Churyumov–Gerasimenko, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko-methods:data analysis, Methods: data analysis, 0103 physical sciences, Size frequency, Cliff, 010303 astronomy & astrophysics, Geomorphology, 0105 earth and related environmental sciences, Remote sensing, Comets: individual: 67P/Churyumov, Gerasimenko, Physics, Ecological niche, Comets: general, geography, geography.geographical_feature_category, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy and Astrophysics, Landslide, biology.organism_classification, 620 Engineering, 13. Climate action, Space and Planetary Science, Water ice, Osiris
Abstract: International audience; We provide a detailed geomorphological and spectrophotometric analysis of the circular niches located on the Seth region of 67P using OSIRIS images. The features can be related to landslide events that occurred on 67P and shaped its surface, as the recent Aswan cliff collapse detected in the same region. We therefore provide an analysis of the area pre- and post-perihelion suggesting that no specific changes have been observed. To assess this, after performing a geomorphological map of the area that allows us to identify different terrain units, we computed the boulders cumulative size frequency distribution (SFD) of the niches, before and after the perihelion passage. The niches SFDs are characterized by a similar trend with two different power-law indices within the same deposit: lower power-law value (between −2.3 and −2.7) for boulders smaller than 5 m and steeper power-law value (between −4.7 and −5.0) for boulders larger than 5 m. These trends suggest that smaller boulders have evolved and progressively have been depleted (lower power-law index), while bigger boulders are more representative of the event that generated the deposit and are less degraded. Then, we perform the spectrophotometric analysis of this region comparing pre- and post-perihelion results. We found colour changes within the area, in particular brighter patches related to the presence of exposed water ice mixed to the refractory materials have been detected in the post-perihelion images.
Published: 2017
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36. Cliffs versus Plains: Can ROSINA/COPS and OSIRIS data of comet 67P/Churyumov-Gerasimenko in autumn 2014 constrain inhomogeneous outgassing?

Author: Stefano Mottola, Yuri V. Skorov, Raphael Marschall, Frank Scholten, Jörg Knollenberg, Ekkehard Kührt, Nicolas Thomas, Martin Rubin, I. L. Lai, H. Sierks, Jong-Shinn Wu, Frank Preusker, Ying Liao, C. C. Su, Kathrin Altwegg, Wing-Huen Ip, Laurent Jorda, J.-B. Vincent, H. U. Keller, 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), and 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)
Subjects: Brightness, 010504 meteorology & atmospheric sciences, data Analysis, Mie scattering, Astrophysics, 01 natural sciences, law.invention, rosetta, modelling, Orbiter, law, 0103 physical sciences, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrometer, biology, Astronomy, Astronomy and Astrophysics, biology.organism_classification, Outgassing, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Sublimation (phase transition), Direct simulation Monte Carlo, Osiris
Abstract: International audience; Context. This paper describes the modelling of gas and dust data acquired in the period August to October 2014 from the European Space Agency's Rosetta spacecraft when it was in close proximity to the nucleus of comet 67P/Churyumov‐Gerasimenko. Aims. With our 3D gas and dust comae models this work attempts to test the hypothesis that cliff activity on comet 67P/Churyumov‐Gerasimenko can solely account for the local gas density data observed by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the dust brightnesses seen by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) in the considered time span. Methods. The model uses a previously developed shape model of the nucleus. From this, the water sublimation rates and gas temperatures at the surface are computed. The gas expansion is modelled with a 3D Direct Simulation Monte Carlo algorithm. A dust drag algorithm is then used to compute dust volume number densities in the coma, which are then converted to brightnesses using Mie theory and a line‐of‐sight integration. Furthermore we have studied the impact of topographic re‐radiation on the models. Results. We show that gas activity from only cliff areas produces a fit to the ROSINA/COPS data that is as statistically good as a purely insolation‐driven model. In contrast, pure cliff activity does not reproduce the dust brightness observed by OSIRIS and can thus be ruled out. On the other hand, gas activity from the Hapi region in addition to cliff activity produces a statistically better fit to the ROSINA/COPS data than purely insolation‐driven outgassing and also fits the OSIRIS observations rather well. We found that topographic re‐radiation does not contribute significantly to the sublimation behaviour of H2O but plays an important role in how the gas flux interacts with the irregular shape of the nucleus. Conclusions. We demonstrate that fits to the observations are non‐unique. We can conclude however that gas and dust activity from cliffs and the Hapi region are consistent with the ROSINA/COPS and OSIRIS data sets for the considered time span and are thus a plausible solution. Models with activity from low gravitational slopes alone provide a statistically inferior solution.
Published: 2017
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37. Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Author: Cesare Barbieri, Nilda Oklay, Giampiero Naletto, Frank Scholten, Xian Shi, V. Da Deppo, Ekkehard Kührt, A. Gicquel, L. M. Lara, J. B. Vincent, Stefano Mottola, Carsten Güttler, P. Lamy, J.-R. Kramm, Géza Kovács, P. J. Gutierrez, Holger Sierks, B. J. R. Davidsson, Francesco Marzari, Jörg Knollenberg, M. De Cecco, M. A. Barucci, Rafael Rodrigo, Laurent Jorda, Stefano Debei, J. L. Bertaux, Marco Fulle, Sonia Fornasier, Marc Hofmann, M. F. A'Hearn, Olivier Groussin, W-H. Ip, I. Hall, Gabriele Cremonese, Clement Feller, Nafiseh Masoumzadeh, Pedro Hasselmann, J. J. Lopez Moreno, H. U. Keller, Ivano Bertini, Stubbe F. Hviid, Cecilia Tubiana, Monica Lazzarin, Ludmilla Kolokolova, Detlef Koschny, Nicolas Thomas, Michael Küppers, Frank Preusker, Hans Rickman, 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, 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), 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), 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), 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), Institute of Space Science, National Central University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), 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), Swedish National Space Board, Ministerio de Economía y Competitividad (España), Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), German Centre for Air and Space Travel, European Space Agency, 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), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Solar System, Brightness, Opposition surge, 010504 meteorology & atmospheric sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Planets and satellites: surfaces, Techniques: photometric, Astrophysics, Coherent backscattering, 01 natural sciences, individual: 67P/Churyumov [Comets], 0103 physical sciences, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Space and Planetary Science, photometric [Techniques], Astronomy, Mars Exploration Program, Phase curve, Moons of Mars, Wavelength, 13. Climate action, Opposition effect, surfaces [Planets and satellites]
Abstract: Aims. We aim to explore the behavior of the opposition effect as an important tool in optical remote sensing on the nucleus of comet 67P/Churyumov-Gerasimenko (67P), using Rosetta-OSIRIS images acquired in different filters during the approach phase, July-August 2014 and the close flyby images on 14 of February 2015, which contain the spacecraft shadow. Methods. We based our investigation on the global and local brightness from the surface of 67P with respect to the phase angle, also known as phase curve. The local phase curve corresponds to a region that is located at the Imhotep-Ash boundary of 67P. Assuming that the region at the Imhotep-Ash boundary and the entire nucleus have similar albedo, we combined the global and local phase curves to study the opposition-surge morphology and constrain the structure and properties of 67P. The model parameters were furthermore compared with other bodies in the solar system and existing laboratory study. Results. We found that the morphological parameters of the opposition surge decrease monotonically with wavelength, whereas in the case of coherent backscattering this behavior should be the reverse. The results from comparative analysis place 67P in the same category as the two Mars satellites, Phobos and Deimos, which are notably different from all airless bodies in the solar system. The similarity between the surface phase function of 67P and a carbon soot sample at extremely small angles is identified, introducing regolith at the boundary of the Imhotep-Ash region of 67P as a very dark and fluffy layer.© ESO, 2017., 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
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38. Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past

Author: Wing-Huen Ip, Laurent Jorda, Carsten Güttler, Detlef Koschny, Michael Küppers, Nicolas Thomas, Monica Lazzarin, Björn Davidsson, Géza Kovács, Cecilia Tubiana, Marc Hofmann, J.-R. Kramm, Philippe Lamy, Maurizio Pajola, Ivano Bertini, M. A. Barucci, Dennis Bodewits, X. Hu, J. Knollenberg, Marco Fulle, J.-B. Vincent, Holger Sierks, M. De Cecco, Luisa Lara, H. U. Keller, Rafael Rodrigo, Stubbe F. Hviid, Frank Scholten, M. Ramy El-Maarry, Jean-Loup Bertaux, Giampiero Naletto, Francesco Marzari, Frank Preusker, Nilda Oklay, A.-T. Auger, Sebastien Besse, Pedro J. Gutiérrez, V. Da Deppo, Z.-Yi Lin, Cesare Barbieri, J. J. Lopez Moreno, Pedro Hasselmann, Sonia Fornasier, Antoine Pommerol, Hans Rickman, M. F. A'Hearn, Jakob Deller, Olivier Groussin, Clement Feller, Simone Marchi, Xian Shi, Stefano Mottola, Gabriele Cremonese, Ekkehard Kührt, J. D. P. Deshapriya, Stefano Debei, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern], 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), NASA Ames Research Center (ARC), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), 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', Universita degli Studi di Padova, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], 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, 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], 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), European Space Agency (ESA), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), Universität Bern [Bern] (UNIBE), NASA-California Institute of Technology (CALTECH), 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)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Weathering, 01 natural sciences, Astrobiology, 0103 physical sciences, Rosetta, OSIRIS, 010303 astronomy & astrophysics, NUCLEUS, 0105 earth and related environmental sciences, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Medicine (all), IMHOTEP REGION, Surface, es, 13. Climate action, Amorphous ice, ROTATION, Environmental science, SHAPE
Abstract: International audience; The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet’s landscape. This suggests that most of the major landforms were created early in the comet’s current orbital configuration. They may even date from earlier if the comet had a larger volatile inventory, particularly of CO or CO2 ices, or contained amorphous ice, which could have triggered activity at greater distances from the Sun.
Published: 2017
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39. Rosetta’s comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature

Author: M. Küppers, Maurizio Pajola, M. L. Lara, Giampiero Naletto, Jean-Loup Bertaux, J. D. P. Deshapriya, J. J. Lopez Moreno, Imre Toth, Ivano Bertini, Nilda Oklay, M. A. Barucci, Frank Scholten, Gabriele Cremonese, M. De Cecco, V. Da Deppo, Marco Fulle, Sonia Fornasier, Wing-Huen Ip, Olivier Groussin, Laurent Jorda, E. Kührt, Holger Sierks, Géza Kovács, Cesare Barbieri, Sebastien Besse, Jakob Deller, J. Knollenberg, Antoine Pommerol, Björn Davidsson, Stefano Debei, Philippe Lamy, R. Kramm, Cecilia Tubiana, C. Güttler, H. U. Keller, Rafael Rodrigo, Monica Lazzarin, Xian Shi, Jean-Baptiste Vincent, Stefano Mottola, Jessica Agarwal, Pedro J. Gutiérrez, Clement Feller, M. Hofmann, Matteo Massironi, Detlef Koschny, Nicolas Thomas, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Francesco Marzari, Frank Preusker, Michael F. A'Hearn, 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), 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, 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), 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), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), 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], Physikalisches Institut [Bern], Universität Bern [Bern], INAF - Osservatorio Astronomico di Trieste (OAT), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), 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), 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), NASA-California Institute of Technology (CALTECH), 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), 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: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, osiris, H2O ICE, 01 natural sciences, EXPOSED WATER ICE, Mantle (geology), Nucleus, Astrobiology, rosetta, comet, 0103 physical sciences, morphology, medicine, surface, virtis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Multidisciplinary, Medicine (all), medicine.anatomical_structure, data, 13. Climate action, [SDU]Sciences of the Universe [physics], Cyclic process, Sublimation (phase transition), Water ice, Surface dust, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: Rosetta observes sublimating surface ices Comets are “dirty snowballs” made of ice and dust, but they are dark because the ice sublimates away, leaving some of the dust behind on the surface. The Rosetta spacecraft has provided a close-up view of the comet 67P/Churyumov-Gerasimenko as it passes through its closest point to the Sun (see the Perspective by Dello Russo). Filacchione et al. detected the spectral signature of solid CO 2 (dry ice) in small patches on the surface of the nucleus as they emerged from local winter. By modeling how the CO 2 sublimates, they constrain the composition of comets and how ices generate the gaseous coma and tail. Fornasier et al. studied images of the comet and discovered bright patches on the surface where ice was exposed, which disappeared as the ice sublimated. They also saw frost emerging from receding shadows. The surface of the comet was noticeably less red just after local dawn, indicating that icy material is removed by sunlight during the local day. Science , this issue p. 1563 , p. 1566 ; see also p. 1536
Published: 2016
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40. The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m

Author: Michael F. A'Hearn, Mohamed Ramy El-Maarry, Holger Sierks, Maurizio Pajola, Nilda Oklay, Luisa Lara, Hans Rickman, Ivano Bertini, Cesare Barbieri, Jakob Deller, Zhong-Yi Lin, Frank Scholten, Giampiero Naletto, Frank Preusker, Jessica Agarwal, Detlef Koschny, N. Thomas, Ekkehard Kührt, S. Höfner, Stefano Mottola, Michael Küppers, Maria Antonietta Barucci, Carsten Güttler, Matteo Massironi, Francesco Marzari, Jörg Knollenberg, Jose J. Lopez Moreno, Stubbe F. Hviid, H. U. Keller, Björn Davidsson, A. Gicquel, Rafael Rodrigo, Cecilia Tubiana, Gabriele Cremonese, Jean-Loup Bertaux, J. Rainer Kramm, Marco Fulle, Fiorangela La Forgia, Stefano Debei, Imre Toth, Monica Lazzarin, Sonia Fornasier, Jean-Baptiste Vincent, Mariolino De Cecco, Philippe Lamy, Jui Chi Lee, Harald Michalik, Steve Boudreault, Vania Da Deppo, Pedro J. Gutiérrez, Alice Lucchetti, Olivier Groussin, Wing-Huen Ip, Laurent Jorda, Marc Hofmann, NASA Ames Research Center (ARC), 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), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Physikalisches Institut [Bern], Universität Bern [Bern], Department of Information Engineering [Padova] (DEI), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], 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), Consejo Superior de Investigaciones Científicas [Madrid] (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 Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), 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), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di 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), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Institute of Computer and Network Engineering [Braunschweig] (IDA), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universität Bern [Bern] (UNIBE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), and California Institute of Technology (CALTECH)-NASA
Subjects: Physics, Comets: individual: 67P/Churyumov-Gerasimenko, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Northern Hemisphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Narrow angle, High resolution, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Comets: general, comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis, Methods: data analysis, Space and Planetary Science, 13. Climate action, 0103 physical sciences, Size frequency, Comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences
Abstract: Aims: We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that lead to these boulder size distributions. Methods: We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 2 May 2015 at a distance of 125 km from the nucleus. The scale of this dataset is 2.3 m/px; the high resolution of the images, coupled with the favorable observation phase angle of 62°, provided the possibility to unambiguously identify boulders ≥7 m on the surface of 67P and to manually extract them with the software ArcGIS. We derived the size-frequency distribution of the illuminated southern hemisphere. Results: We found a power-law index of -3.6 ± 0.2 for the boulders on the southern hemisphere with a diameter range of 7-35 m. The power-law index is equal to the one previously found on northern and equatorial regions of 67P, suggesting that similar boulder formation processes occur in both hemispheres. The power-law index is related to gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. In addition, the presence of a larger number of boulders per km2 in the southern hemisphere, which is a factor of 3 higher with respect to the northern hemisphere, suggests that the southernmost terrains of 67P are affected by a stronger thermal fracturing and sublimating activity, hence possibly causing larger regressive erosion and gravitational events.
Published: 2016
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41. The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and its satellites

Author: Frank Fueten, Veronique Ansan, E. Kersten, Ernst Hauber, Jonas Bostelmann, M. Spiegel, Frank Scholten, Sebastian Walter, Alexander Dumke, T. Roatsch, Konrad Willner, G. Neukum, Patrick Pinet, Daniela Tirsch, S. van Gasselt, Dennis Reiss, Stephan Elgner, Patrick C. McGuire, R. Jaumann, Frank Preusker, Harald Hoffmann, N. M. Hoekzema, Volker Mertens, Juergen Oberst, K. Gwinner, Damien Loizeau, H. Hiesinger, Klaus-Dieter Matz, Robert Stesky, Ralph Schmidt, G. Erkeling, Marita Wählisch, A. Pasewaldt, Gregory Michael, Christian Heipke, DLR Institute of Planetary Research, German Aerospace Center (DLR), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Chercheur indépendant, Technische Universität Berlin (TU), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Freie Universität Berlin, Institut für Planetologie [Münster], Westfälische Wilhelms-Universität Münster (WWU), Department of Earth Sciences [St. Catharines], Brock University [Canada], Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-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), Institut de génétique et biologie moléculaire et cellulaire (IGBMC), and Université Louis Pasteur - Strasbourg I-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Planetary mapping, 010504 meteorology & atmospheric sciences, Mars, Context (language use), 01 natural sciences, 3D dataanalysis, Phobos, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, topography, 0103 physical sciences, 010303 astronomy & astrophysics, Image resolution, 0105 earth and related environmental sciences, Remote sensing, Planetary topography, Pixel, Orthophoto, Astronomy and Astrophysics, Mars Exploration Program, Moons of Mars, Stereo imaging, Mars Phobos Planetary, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Photogrammetry, 3D data analysis, Surface reconstruction, High Resolution Stereo Camera, Geology
Abstract: The High Resolution Stereo Camera (HRSC) of ESA׳s Mars Express is designed to map and investigate the topography of Mars. The camera, in particular its Super Resolution Channel (SRC), also obtains images of Phobos and Deimos on a regular basis. As HRSC is a push broom scanning instrument with nine CCD line detectors mounted in parallel, its unique feature is the ability to obtain along-track stereo images and four colors during a single orbital pass. The sub-pixel accuracy of 3D points derived from stereo analysis allows producing DTMs with grid size of up to 50 m and height accuracy on the order of one image ground pixel and better, as well as corresponding orthoimages. Such data products have been produced systematically for approximately 40% of the surface of Mars so far, while global shape models and a near-global orthoimage mosaic could be produced for Phobos. HRSC is also unique because it bridges between laser altimetry and topography data derived from other stereo imaging instruments, and provides geodetic reference data and geological context to a variety of non-stereo datasets. This paper, in addition to an overview of the status and evolution of the experiment, provides a review of relevant methods applied for 3D reconstruction and mapping, and respective achievements. We will also review the methodology of specific approaches to science analysis based on joint analysis of DTM and orthoimage information, or benefitting from high accuracy of co-registration between multiple datasets, such as studies using multi-temporal or multi-angular observations, from the fields of geomorphology, structural geology, compositional mapping, and atmospheric science. Related exemplary results from analysis of HRSC data will be discussed. After 10 years of operation, HRSC covered about 70% of the surface by panchromatic images at 10–20 m/pixel, and about 97% at better than 100 m/pixel. As the areas with contiguous coverage by stereo data are increasingly abundant, we also present original data related to the analysis of image blocks and address methodology aspects of newly established procedures for the generation of multi-orbit DTMs and image mosaics. The current results suggest that multi-orbit DTMs with grid spacing of 50 m can be feasible for large parts of the surface, as well as brightness-adjusted image mosaics with co-registration accuracy of adjacent strips on the order of one pixel, and at the highest image resolution available. These characteristics are demonstrated by regional multi-orbit data products covering the MC-11 (East) quadrangle of Mars, representing the first prototype of a new HRSC data product level.
Published: 2016
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42. High resolution Vesta High Altitude Mapping Orbit (HAMO) Atlas derived from Dawn framing camera images

Author: Ralf Jaumann, Carol A. Raymond, Frank Preusker, Frank Scholten, Klaus-Dieter Matz, Elke Kersten, Christopher T. Russell, and Thomas Roatsch
Subjects: Asteorids, Framing (visual arts), Pixel, Space and Planetary Science, Asteroid, High resolution, Astronomy and Astrophysics, Vesta Carography, Effects of high altitude on humans, Geology, Remote sensing
Abstract: The Dawn framing camera (FC) acquired about 2500 clear filter images of Vesta with a resolution of about 70 m/pixels during the High Altitude Mapping Orbit (HAMO) in fall 2011. We ortho-rectified these images and produced a global high resolution controlled mosaic of Vesta. This global mosaic is the baseline for a high resolution Vesta atlas that consists of 15 tiles mapped at a scale of 1:500,000. The nomenclature used in this atlas was proposed by the Dawn team and was approved by the International Astronomical Union (IAU). The whole atlas is available to the public through the Dawn GIS web page [ http://dawn_gis.dlr.de/atlas ].
Published: 2012
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43. The geomorphology of (21) Lutetia: Results from the OSIRIS imaging system onboard ESA's Rosetta spacecraft

Author: Cesare Barbieri, Olivier Groussin, Ekkehard Kührt, M. Küppers, Matteo Massironi, Laurent Jorda, Jean-Baptiste Vincent, Simone Marchi, Holger Sierks, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Colin Snodgrass, Elena Martellato, Hans Rickman, Richard Moissl, M. A. Barucci, R. Rodrigo, Cecilia Tubiana, Sonia Fornasier, Frank Scholten, Sebastien Besse, Katrin Stephan, K. P. Wenzel, H. U. Keller, F. Preusker, Detlef Koschny, Nicolas Thomas, Gabriele Cremonese, Francesco Marzari, P. L. Lamy, Physikalisches Institut [Bern], Universität Bern [Bern], 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), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], 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, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica, Dipartimento di Geoscienze [Padova], DLR Institute of Planetary Research, German Aerospace Center (DLR), 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), Observatoire de Paris - Site de Paris (OP), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre Jean Perrin [Clermont-Ferrand] (UNICANCER/CJP), UNICANCER, Imagerie Moléculaire et Thérapie Vectorisée (IMTV), Université d'Auvergne - Clermont-Ferrand I (UdA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Cancéropôle CLARA-ITMO ' Technologies pour la Santé ', European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), European Space Astronomy Centre (ESAC), Universität Bern [Bern] (UNIBE), 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), 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), and ITMO ' Technologies pour la Santé '-Cancéropôle CLARA-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université d'Auvergne - Clermont-Ferrand I (UdA)
Subjects: 010504 meteorology & atmospheric sciences, Lineament, Data analysis, Terrain, 01 natural sciences, Imaging, Impact crater, Rosetta, 0103 physical sciences, Ejecta, 010303 astronomy & astrophysics, Geomorphology, 0105 earth and related environmental sciences, [PHYS]Physics [physics], geography, geography.geographical_feature_category, Asteroid, Astronomy and Astrophysics, Landslide, Geophysics, Radius, Lutetia, 13. Climate action, Space and Planetary Science, Ridge, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: International audience; The surface of (21) Lutetia is highly complex with significant interactions between ancient and more recent structures. This work attempts to summarize the surface geomorphology observed using the high resolution images from OSIRIS, the imaging system onboard the European Space Agency's Rosetta spacecraft. A wide range of surface morphologies are seen including heavily cratered terrain, extensive sets of lineaments, young impact craters, and a ridge, the height of which is more than 1/5th of the mean radius of the body. Very young and very old terrains (as inferred from crater densities) are seen in close proximity. The longest continuous lineament is over 80 km long. The lineaments show regional-dependent organization and structure. Several categories of lineament can be described. Lineaments radial to impact craters as seen on other asteroidal bodies are mostly absent. Although the lineaments may be of seismic origin (and possibly the result of several impact-induced events), impacts producing recent large craters place constraints on seismic phenomena. In particular, stronger attenuation of shocks than seen on other asteroidal bodies seems to be required. Inhomogeneous energy transport, possibly matching observed inhomogeneous ejecta deposition may offer explanations for some of the observed phenomena. Some impact craters show unusual forms, which are probably the result of impact into a surface with relief comparable to the resultant crater diameter and/or oblique impact. There is evidence that re-surfacing through landslides has occurred at several places on the object. (C) 2011 Elsevier Ltd. All rights reserved.
Published: 2012
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44. High-resolution atlas of Rhea derived from Cassini-ISS images

Author: Angelika Hoffmeister, G. Neukum, Klaus-Dieter Matz, Tilmann Denk, E. Kersten, Roland Wagner, Marita Wählisch, Carolyn C. Porco, T. Roatsch, and Frank Scholten
Subjects: Rhea, Atlas (topology), Astronomy, High resolution, Astronomy and Astrophysics, Planetary Data System, Astrobiology, Icy Satellites, Saturn, Space and Planetary Science, Imaging science, Enceladus, Geology, Saturnian system
Abstract: The Cassini Imaging Science Subsystem (ISS) acquired 370 high-resolution images ( http://ciclops.org/maps 〉 and the Planetary Data System 〈 http://pds.jpl.nasa.gov 〉. This atlas completes the series of the atlases of the Saturnian medium-sized satellites Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus.
Published: 2012
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45. Morphology of the cloud tops as observed by the Venus Express Monitoring Camera

Author: Frank Scholten, Jonas Hesemann, Richard Moissl, Li Song, Stubbe F. Hviid, Agustín Sánchez-Lavega, Thomas Roatsch, Dmitrij V. Titov, Larry W. Esposito, David Crisp, Klaus-Dieter Matz, Sanjay S. Limaye, Nikolay Ignatiev, H. U. Keller, Miguel Almeida, Wojciech J. Markiewicz, and Ralf Jaumann
Subjects: Brightness, Cloud morphology, biology, Polar orbit, Astronomy, Astronomy and Astrophysics, Venus, biology.organism_classification, Venus Monitoring Camera, UV imaging, Space and Planetary Science, Planet, Nadir, Polar, Satellite, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Geology, Convection cell
Abstract: Since the discovery of ultraviolet markings on Venus, their observations have been a powerful tool to study the morphology, motions and dynamical state at the cloud top level. Here we present the results of investigation of the cloud top morphology performed by the Venus Monitoring Camera (VMC) during more than 3 years of the Venus Express mission. The camera acquires images in four narrow-band filters centered at 365, 513, 965 and 1010 nm with spatial resolution from 50 km at apocentre to a few hundred of meters at pericentre. The VMC experiment provides a significant improvement in the Venus imaging as compared to the capabilities of the earlier missions. The camera discovered new cloud features like bright “lace clouds” and cloud columns at the low latitudes, dark polar oval and narrow circular and spiral “grooves” in the polar regions, different types of waves at the high latitudes. The VMC observations revealed detailed structure of the sub-solar region and the afternoon convective wake, the bow-shape features and convective cells, the mid-latitude transition region and the “polar cap”. The polar orbit of the satellite enables for the first time nadir viewing of the Southern polar regions and an opportunity to zoom in on the planet. The experiment returned numerous images of the Venus limb and documented global and local brightening events. VMC provided almost continuous monitoring of the planet with high temporal resolution that allowed one to follow changes in the cloud morphology at various scales. We present the in-flight performance of the instrument and focus in particular on the data from the ultraviolet channel, centered at the characteristic wavelength of the unknown UV absorber that yields the highest contrasts on the cloud top. Low latitudes are dominated by relatively dark clouds that have mottled and fragmented appearance clearly indicating convective activity in the sub-solar region. At ∼50° latitude this pattern gives way to streaky clouds suggesting that horizontal, almost laminar, flow prevails here. Poleward from about 60°S the planet is covered by almost featureless bright polar hood sometimes crossed by dark narrow (∼300 km) spiral or circular structures. This global cloud pattern can change on time scales of a few days resulting in global and local “brightening events” when the bright haze can extend far into low latitudes and/or increase its brightness by 30%. Close-up snapshots reveal plenty of morphological details like convective cells, cloud streaks, cumulus-like columns, wave trains. Different kinds of small scale waves are frequently observed at the cloud top. The wave activity is mainly observed in the 65–80° latitude band and is in particular concentrated in the region of Ishtar Terra that suggests their possible orographic origin. The VMC observations have important implications for the problems of the unknown UV absorber, microphysical processes, dynamics and radiative energy balance at the cloud tops. They are only briefly discussed in the paper, but each of them will be the subject of a dedicated study.
Published: 2012
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46. The northern hemisphere of asteroid (21) Lutetia-topography and orthoimages from Rosetta OSIRIS NAC image data

Author: Stefano Mottola, Frank Preusker, Klaus-Dieter Matz, N. Thomas, Frank Scholten, Jörg Knollenberg, Ekkehard Kührt, and Thomas Roatsch
Subjects: 010504 meteorology & atmospheric sciences, Digital terrain models, 01 natural sciences, Orthoimages, 0103 physical sciences, Rosetta, OSIRIS, Digital elevation model, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Pixel, biology, Orientation (computer vision), Asteroid, Orthophoto, Astronomy and Astrophysics, computer.file_format, biology.organism_classification, Lutetia, Photogrammetry, Space and Planetary Science, Raster graphics, Osiris, computer, Geology
Abstract: During the flyby at asteroid (21) Lutetia by the Rosetta spacecraft in July 2010 the OSIRIS imaging system onboard acquired several hundred images of Lutetia's surface. Images of the OSIRIS NAC (Narrow Angle Camera) comprise up to 60 m/pixel ground resolution. We analyzed 84 multi spectral NAC images with stereo photogrammetric methods. A 3D point control network within a photogrammetric block adjustment was used to derive improved orientation data (pointing and position) for the Rosetta spacecraft as well as corrections of the pre flight estimates of Lutetia's position in space. For the generation of a digital terrain model (DTM) we selected a subset of 10 OSIRIS NAC images within a multi image matching process. We combined the matching results with the adjusted orientation data and derived more than 12 million of surface points with a 3D point accuracy of similar to 40 m (2/3 pixel) and a vertical component of that of similar to 15 m (1/4 pixel). The 3D surface points were converted to a final 60 m raster DIM which covers about 78 of the entire northern hemisphere. All 84 NAC images were then ortho rectified on the basis of the improved orientation and the DTM. Thus orthoimage products with sub pixel registration accuracy are available for multi spectral mapping of the surface of Lutetia. Finally the DIM was textured with an orthoimage mosaic to form a VRML dataset for full resolution interactive 3D investigations. (C) 2012 Elsevier Ltd. All rights reserved.
Published: 2012

47. Hollows on Mercury: MESSENGER Evidence for Geologically Recent Volatile-Related Activity

Author: Juergen Oberst, Brett W. Denevi, D. M. Hurwitz, David M.H. Baker, S. E. Braden, Noam R. Izenberg, Nancy L. Chabot, Frank Scholten, Carolyn M. Ernst, James W. Head, Timothy J. McCoy, Zhiyong Xiao, David T. Blewett, Larry R. Nittler, Frank Preusker, Sean C. Solomon, Scott L. Murchie, and Caleb I. Fassett
Subjects: Multidisciplinary, Messenger, Geochemistry, Pyroclastic rock, chemistry.chemical_element, Mercury, Volcanism, Space weathering, Mercury (element), Astrobiology, Outgassing, volatiles, hollows, chemistry, Impact crater, Planet, Formation and evolution of the Solar System, Geology
Abstract: High-resolution images of Mercury's surface from orbit reveal that many bright deposits within impact craters exhibit fresh-appearing, irregular, shallow, rimless depressions. The depressions, or hollows, range from tens of meters to a few kilometers across, and many have high-reflectance interiors and halos. The host rocks, which are associated with crater central peaks, peak rings, floors, and walls, are interpreted to have been excavated from depth by the crater-forming process. The most likely formation mechanisms for the hollows involve recent loss of volatiles through some combination of sublimation, space weathering, outgassing, or pyroclastic volcanism. These features support the inference that Mercury's interior contains higher abundances of volatile materials than predicted by most scenarios for the formation of the solar system's innermost planet.
Published: 2011
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48. Concatenation of HRSC colour and OMEGA data for the determination and 3D-parameterization of high-altitude CO2 clouds in the Martian atmosphere

Author: Frank Scholten, Brigitte Gondet, Franck Montmessin, Ernst Hauber, Harald Hoffmann, Anni Määttänen, DLR Institute of Planetary Research, German Aerospace Center (DLR), 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), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmosphere, Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Astronomy, Astronomy and Astrophysics, Atmosphere of Mars, Mars Exploration Program, 01 natural sciences, Latitude, Carbon dioxide, 13. Climate action, Space and Planetary Science, Clouds, Local time, 0103 physical sciences, 010303 astronomy & astrophysics, Shortwave, Geology, 0105 earth and related environmental sciences, Tharsis
Abstract: International audience; We used Mars Express HRSC and OMEGA data to investigate mesospheric cloud features observed in the equatorial belt of Mars from December 2007 until early March 2008. This period corresponds to early northern spring of Martian year 29. The reflection peak at 4.26 µm in OMEGA data identifies the clouds as CO2 ice clouds. HRSC observed the clouds together with OMEGA in five orbits. Cloud features are most prominent in the shortwave HRSC colour channels with wavelength centers at 440 nm and 530 nm, but rarely visible in all other channels. In the period of Ls 0°-36°, OMEGA and HRSC together detected mesospheric CO2 ice clouds in 40 orbits. They occur in a latitude belt of ±20° around the equator and at longitudes between 240°E (Tharsis) in the West and 30°E (Sinus Meridiani) in the East. The clouds were observed between 3 pm and 5 pm local time with mainly ripple-like to filamentary cloud forms. The viewing angles of the HRSC blue and green colour channels differ by 6.6° and the resulting parallax can be used to directly measure cloud heights by means of ray intersection. 17 HRSC data takes were found to exhibit clouds with heights from 66 km to 83 km with an accuracy of 1-2 km. The pushbroom imaging technique also yields a time delay for the two observations in the order of 5 to 15 seconds close to periapsis, and therefore time-related cloud movements can be detected. A method was developed to determine the across-track cloud displacements, which can directly be translated to wind velocities. Zonal cloud movements could be measured in 13 cases and were oriented from East to West. Related wind speeds range between 60-93 m/s with an accuracy of 10-13 m/s.
Published: 2010
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49. Topography of Mars from global mapping by HRSC high-resolution digital terrain models and orthoimages: Characteristics and performance

Author: T. Roatsch, Frank Scholten, Ralf Jaumann, Juergen Oberst, Christian Heipke, Frank Preusker, Stephan Elgner, Michael Spiegel, Ralph Schmidt, and Klaus Gwinner
Subjects: Orientation (computer vision), Terrain, Mars Exploration Program, Mars global planetary mapping stereo imaging digital terrain model orthoimage, Geodesy, Geophysics, Stereo imaging, Space and Planetary Science, Geochemistry and Petrology, Mars Orbiter Laser Altimeter, Earth and Planetary Sciences (miscellaneous), Digital elevation model, Geology, Stereo camera, High Resolution Stereo Camera, Remote sensing
Abstract: We report on the results of the Mars Express High-Resolution Stereo Camera (HRSC) experiment pertaining to one of its major aims, mapping the surface of Mars by high-resolution digital terrain models (DTM, up to 50 m grid spacing) and orthoimages (up to 12.5 m resolution). We introduce the specifications and characteristics of these data products and give an overview of the procedures that have been developed and are applied for their derivation. We also address the performance characteristics of the mapping project related to different aspects of internal accuracy, accuracy with respect to the global reference system, and regional aspects. Using adaptive processing techniques for terrain reconstruction and a revised approach to the improvement of orientation data, a mean precision of the resulting 3D points of about 12 m is obtained, exceeding the mean ground resolution of the stereo images. Using Mars Orbiter Laser Altimeter (MOLA) data, the HRSC models are firmly tied to the global reference system at the scale of the HRSC DTM grid spacing in the lateral dimension, and to within few meters vertically. HRSC high-resolution DTMs are typically generated using a grid size of about 2 times the mean ground resolution, but usually not larger than 3 times the mean ground resolution, and not smaller than 3 times the precision of the integrated 3D points derived from stereo image analysis. Statistically, every grid cell is based on at least one measured 3D point. Thus, horizontal DTM resolution is well established with regard to the precision and density of the derived 3D points, while the concurrent aim of a detailed terrain representation at maximum possible resolution is pursued. Comparison with the DTM derived from MOLA data allows us to identify specific advancements related to this updated view of Martian topography. We also address the mapping performance of HRSC in comparison to MOLA with respect to latitude and to different surface types and morphologies. Finally, comparison with MOLA highlights typical complementarities of the two different approaches for mapping planetary surfaces.
Published: 2010
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50. Derivation and Validation of High-Resolution Digital Terrain Models from Mars Express HRSC Data

Author: Bernd Giese, Ralf Jaumann, Jürgen Oberst, Frank Scholten, Michael Spiegel, Ralph Schmidt, Gerhard Neukum, Christian Heipke, and Klaus Gwinner
Subjects: Stereo imaging, Geography, Photogrammetry, Terrain, Image processing, Mars Exploration Program, Computers in Earth Sciences, Scale (map), Image resolution, High Resolution Stereo Camera, Remote sensing
Abstract: The High Resolution Stereo Camera (HRSC) onboard the Mars Express mission is the first photogrammetric stereo sensor system employed for planetary remote sensing. The derivation of high-quality digital terrain models is subject to a variety of parameters, some of which show a significant variability between and also within individual datasets. Therefore, adaptive processing techniques and the use of efficient quality parameters for controlling automated processing are considered to be key requirements for DTM generation. We present the general procedure for the derivation of HRSC high-resolution DTM, representing the core element of the systematic derivation of high-level data products by the Mars Express HRSC experiment team. We also analyze test series applying specific processing variations, including a new method for signal adaptive image preprocessing. The results are assessed based on internal quality measures and compared to external terrain data. Sub-pixel scale 3D point accuracy of better than 10 m and a DTM spatial resolution of up to 50 m can be achieved for large parts of the surface of Mars within a reasonable effort. This confirms the potentials of the applied along-track multiple stereo imaging principle and allows for a considerable improvement in our knowledge of the topography of Mars.
Published: 2009
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