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160 results on '"Asteroiden und Kometen"'

1. Convex Shape and Rotation Model of Lucy Target (11351) Leucus from Lightcurves and Occultations

Author: Simone Marchi, Harold F. Levison, Stefano Mottola, Marc W. Buie, Amanda M. Zangari, S. Hellmich, and Michael E. Brown
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Rotation period, Asteroiden und Kometen, Ecliptic coordinate system, Planetengeodäsie, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Phase curve, Light curves, Light curve, Stellar occultation, Occultation, Jupiter trojans, Geophysics, Space and Planetary Science, Sidereal time, Geometric albedo, Orientation (geometry), Earth and Planetary Sciences (miscellaneous), Astrophysics::Earth and Planetary Astrophysics, CCD photometry, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report new photometric lightcurve observations of the Lucy Mission target (11351) Leucus acquired during the 2017, 2018, and 2019 apparitions. We use these data in combination with stellar occultations captured during five epochs to determine the sidereal rotation period, the spin axis orientation, a convex shape model, the absolute scale of the object, its geometric albedo, and a model of the photometric properties of the target. We find that Leucus is a prograde rotator with a spin axis located within a sky-projected radius of 3° (1σ) from J2000 Ecliptic coordinates (λ = 208°, β = +77°) or J2000 Equatorial Coordinates (R.A. = 248°, decl. = +58°). The sidereal period is refined to P sid = 445.683 ± 0.007 h. The convex shape model is irregular, with maximum dimensions of 60.8, 39.1, and 27.8 km. The convex model accounts for global features of the occultation silhouettes, although minor deviations suggest that local and global concavities are present. We determine a geometric albedo of p V = 0.043 ± 0.002. The derived phase curve supports a D-type classification for Leucus.
Published: 2020
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2. 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

3. Near-perihelion activity of comet 67P/Churyumov-Gerasimenko. A first attempt of non-static analysis

Author: Yuri V. Skorov, Stefano Mottola, Paul Hartogh, and Horst Uwe Keller
Subjects: Area fraction, Physics, 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Planetengeodäsie, food and beverages, Astronomy and Astrophysics, Mechanics, Penetration (firestop), Sunset, Static analysis, Heat wave, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Thermal, numerical methods, Polar, Sublimation (phase transition), comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The observed rate of water production of comet 67P/Churyumov–Gerasimenko near its perihelion can be approximated by a very steep power function of the heliocentric distance. Widely used thermophysical models based on a static dust layer on top of the icy/refractory matrix are poorly consistent with these observations. We analyse published model results and demonstrate that thermophysical models with a uniform and static ice free layer do not reproduce the observed steep water production rates of 67P near perihelion. Based on transient thermal modeling we conclude that the accelerated gas activity can be explained assuming that the active area fraction near the south pole is increased. The deeper penetration of the heat wave during polar day (no sunset) can activate sublimation through thicker inert dust layers. This can also lead to removal of thicker dust layers and consequently to an expansion of the active area.
Published: 2020
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4. Asymmetric Craters on the Dwarf Planet Ceres—Results of Second Extended Mission Data Analysis

Author: Krohn, Katrin, Jaumann, Ralf, Wickhusen, Kai, Otto, Katharina A., Kersten, Elke, Stephan, Katrin, Wagner, Roland, Raymond, Carol A., and Russell, Christopher T.
Subjects: Asteroiden und Kometen, asteroids, subsurface ice, dwarf planets, asymmetrical cratering, Planetengeodäsie, Dawn, cratering processes, Planetengeologie, XM2, influence of slopes, Ceres, crater formation, asymmetric craters, crater formation on small bodies
Abstract: After almost three years of successful operation on Ceres, the Dawn spacecraft entered its last orbits around the dwarf planet and obtained a set of high-resolution images of 3 to 5 m/pixel. These images reveal a variety of morphologic features, including a set of asymmetric crater morphologies as observed earlier in the mission on the asteroid Vesta. We identified 269 craters, which are located between 60&deg, N to 60&deg, S latitude and 197&deg, E to 265&deg, E longitude, and investigated their morphological characteristics using a digital terrain model (DTM). These craters range in diameter from 0.30 to 4.2 km, and exhibit a sharp crater rim on the uphill side and a smooth one on the downhill side. We found that all asymmetric craters are formed on a sloping surface with the majority appearing at slope angles between 5 and 20 degrees. This implies that, as observed on Vesta, the topography is the main cause for these asymmetries.
Published: 2019
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5. Pinnacles on the surface of the comet 67P/Churyumov-Gerasimenko: regional distribution and morphology

Author: Alexander T. Basilevsky, Urs Mall, Horst Uwe Keller, Stubbe F. Hviid, Yuri V. Skorov, and S. S. Krasilnikov
Subjects: Physics, Surface (mathematics), Asteroiden und Kometen, Morphology (linguistics), Distribution (number theory), Space and Planetary Science, Asteroid, Comet, Astronomy and Astrophysics, 67P/Churyumov-Gerasimenko Comets Rosetta, Astrobiology
Abstract: Pinnacles are local topographic promontories of different shapes considered to be formed due to uneven surface erosion. In the case of comets, areal changes in the degree of erosion could be related to inhomogeneities of the nucleus. However, the amount of solar radiation and the thermal gradient is different across the orbit for geomorphological regions, which can result in different erosion and shape for a similar composition among two differently illuminated areas. Therefore, a study of the areal distribution of pinnacles on the nucleus surface and their morphology may help to understand the structure and properties of the nucleus material. We mapped 166 pinnacles on the comet nucleus surface of 67P/Churyumov-Gerasimenko. About a third of them have planimetrically rounded shape (rounded pinnacles) and the rest are planimetrically elongated (local ridges). In the southern hemisphere, number of both round pinnacles and local ridges is larger than in the northern hemisphere. This difference possibly indicates the higher effectiveness of the pinnacles’ formation in the southern hemisphere. At the same time the mean values of the measured parameters, including the height, show no statistically reliable difference between the north and south. We found that the maximum height of the pinnacles is about a hundred meters. Suggesting that they have been formed by sublimational erosion, this value allows estimating the minimum thickness of the eroded material and thus the degree of the evolutionary changes of the nucleus. In our future study, we will model pinnacles formation based on the here presented analysis of observations.
Published: 2019
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6. Revisiting the Analysis of the MARA Measurements on Ryugu’s Surface with a Multi-Scale Shape Model

Author: Hamm, Maximilian, Grott, Matthias, DeWiljes, J., Knollenberg, Jörg, Scholten, Frank, Matz, K-D, Preusker, Frank, Biele, Jens, Elgner, Stephan, Ogawa, Kazunori, Sakatani, N., Senshu, H., Okada, Junpei, Jaumann, R., Sugita, S., and Tanaka, S.
Subjects: Planetengeologie, Asteroiden und Kometen, Planetenphysik, Institut für Planetenforschung, Planetengeodäsie, MASCOT MARA Hayabusa2 Asteroids Ryugu Thermal Modeling Regolith, Nutzerzentrum für Weltraumexperimente (MUSC)
Abstract: The measurents of the MASCOT Radiometer MARA are revisited and a detailed thermal model of the MASCOT environment is presented.
Published: 2019

7. Analysis of night-side dust activity on comet 67P observed by VIRTIS-M: a new method to constrain the thermal inertia on the surface

Author: Rinaldi, G., Formisano, M., Kappel, D., Capaccioni, F., Bockelée-Morvan, D., Cheng, Y.-C., Vincent, J.-B., Deshapriya, P., Arnold, G., Capria, M., Ciarniello, M., D’Aversa, E., D'aversa, E, De Sanctis, M., Doose, L., Erard, S., Federico, C., Filacchione, G., Fink, U., Leyrat, C., Longobardo, A., Magni, G., Migliorini, A., Mottola, S., Naletto, G., Raponi, A., Taylor, F., Tosi, F., Tozzi, G., Salatti, M., IASI (IASI), Consiglio Nazionale delle Ricerche (CNR), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), 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), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Mécanique Textiles (LPMT), ENSITM-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), IASF-Roma - Istituto di Astrofisica Spaziale e Fisica cosmica - Roma, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Instituto de Estudos Avançados (IEAV), Institut, DLR Institute of Planetary Research, German Aerospace Center (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto di Fisica dello Spazio Interplanetario (IFSI), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-ENSITM-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Padova = University of Padua (Unipd), and Bockelée-Morvan, Dominique
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko -infrared, 010504 meteorology & atmospheric sciences, Comet, Imaging spectrometer, Coma (optics), Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], 01 natural sciences, general -comets, Mantle (geology), [SDU] Sciences of the Universe [physics], comet, 0103 physical sciences, Thermal, comets, individual, infrared: planetary systems, 010303 astronomy & astrophysics, planetary systems, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Jet (fluid), Range (particle radiation), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, Leitungsbereich PF, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Plume, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: On 2015 July 18, near perihelion at a heliocentric distance of 1.28 au, the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-M) on board the Rosetta spacecraft had the opportunity of observing dust activity in the inner coma with a view of the night side (shadowed side) of comet 67P/Churyumov-Gerasimenko. At the time of the measurements we present here, we observe a dust plume that originates on the far side of the nucleus. We are able to identify the approximate location of its source at the boundary between the Hapi and Anuket regions, and we find that it has been in darkness for some hours before the observation. Assuming that this time span is equal to the conductive time scale, we obtain a thermal inertia in the range 25–36 W K−1 m−2 s−1/2. These thermal inertia values can be used to verify with a 3D finite-element method (FEM) numerical code whether the surface and subsurface temperatures agree with the values found in the literature. We explored three different configurations: (1) a layer of water ice mixed with dust beneath a dust mantle of 5 mm with thermal inertia of 36 J m−2 K−1 s−0.5; (2) the same structure, but with thermal inertia of 100 J m−2 K−1 s−0.5; (3) an ice-dust mixture that is directly exposed. Of these three configurations, the first seems to be the most reasonable, both for the low thermal inertia and for the agreement with the surface and subsurface temperatures that have been found for the comet 67P/Churyumov-Gerasimenko. The spectral properties of the plume show that the visible dust color ranged from 16 ± 4.8%/100 nm to 13 ± 2.6%/100 nm, indicating that this plume has no detectable color gradient. The morphology of the plume can be classified as a narrow jet that has an estimated total ejected mass of between 6 and 19 tons when we assume size distribution indices between −2.5 and −3.
Published: 2019
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8. Geometric preprocessing for Rosetta/VIRTIS-M measurements of comet 67P/C-G

Author: Kappel, David, Arnold, Gabriele, Moroz, Liubov, Raponi, A., Ciarniello, M., Tosi, F., Erard, S., Leyrat, C., Blecka, M., Filacchione, G., and Capaccioni, F.
Subjects: Asteroiden und Kometen, Leitungsbereich PF, Rosetta, Comet 67P, Geometry, VIRTIS
Abstract: Following earlier surface spectrophotometric analyses of Rosetta/VIRTIS-M measurements of comet 67P/Churyumov-Gerasimenko (hereafter 67P), we refine the instrument's geometric registration model and spatial consistency of the radiometric calibration. For this purpose we compare measured 67P nucleus images from the entire mission to corresponding photometric simulations and determine an optical distortion map between them. The refinements will allow us to improve the retrieval of physical and compositional surface properties of the comet's nucleus.
Published: 2019

9. Dust composition in the innermost coma of comet 67P from the VIRTIS-M spectra: Organic features detection

Author: Rinaldi, G., D'Aversa, E., Bockelee-Morvan, D., Raponi, A, Capaccioni, F., Ciarniello, M., Filacchione, G., De Sanctis, M. C., Oliva, F., Kappel, David, Longobardo, A, Tosi, F., Capria, M., and Taylor, F.
Subjects: Asteroiden und Kometen, Rosetta, Comet 67P, Dust, VIRTIS
Abstract: The Rosetta/ESA spacecraft followed the comet 67P/Churyumov-Gerasimenko from 2014 August (3.6 au pre-perihelion) to 2016 September (3.6 au post-perihelion). This offered a unique opportunity to analyze the time evolution of the dust properties in the inner coma. Onboard Rosetta, the Visual Infrared and Thermal Imaging Spectrometer (VIRTIS-M) acquired spectra of the dust coma in the spectral range 0.25 to 5 μm.
Published: 2019

10. The HP³ Radiometer on InSight

Author: Mueller, N., Grott, M., Piqueux, S., Spohn, T., Smrekar, S.E., Knollenberg, J., Hudson, T.L., Spiga, A., Forget, F., Millour, E., Lemmon, M.T., Maki, J., Golombek, M., and Banerdt, W.B.
Subjects: Asteroiden und Kometen, Planetenphysik, Leitungsbereich PF, Astrophysics::Solar and Stellar Astrophysics, Mars, Messung, Astrophysics::Earth and Planetary Astrophysics, Oberflächentemperatur, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, Physics::Geophysics
Abstract: The Heat Flow and Physical Properties Package (HP³) includes an infrared Radiometer attached to the deck of the InSight lander. The radiometer will observe the seasonal temperature variation over the course of the mission. Fitting of diurnal temperature curves and of the response to eclipses provides an estimate of thermophysical properties of the near surface, and possibly constrains atmospheric variables such as the ratio of visible to infrared dust opacity.
Published: 2019

11. Bouncing boulders on comet 67P

Author: Vincent, Jean-Baptiste, Birch, S., Hayes, A., Zacny, K., Oklay, N., and Cambianica, P.
Subjects: Asteroiden und Kometen, boulders, 67P, comets
Published: 2019

12. The HP3 Radiometer on InSight

Author: Müller, Nils, Grott, Matthias, Piqueux, S., Spohn, Tilman, Smrekar, S., Knollenberg, Jörg, Hudson, T.L., Spiga, Aymeric, Forget, F., Millour, Ehouarn, Lemmon, M. T., Maki, J., Golombek, M., and Banerdt, W.B.
Subjects: Asteroiden und Kometen, Planetenphysik, Institutsplanung / Zentrale Aufgaben PF, Mars, Messung, Oberflächentemperatur
Abstract: Introduction: The Heat Flow and Physical Properties Package (HP³) includes an infrared Radiometer attached to the deck of the InSight lander. The main objective of this part of the instrument is to con-strain the surface thermal boundary condition for the heat flow derivation by the instrumented tether de-ployed into the subsurface. The heat flow in the subsurface can be affected by seasonal and diurnal temperature variations, by radiation from the lander, its shadow, and the change in surface albedo caused by dust removal during landing and later deposition. The radiometer will observe the seasonal variation over the course of the mission. Fitting of diurnal temperature curves provides an estimate of albedo and other thermophysical properties of the near surface.
Published: 2019

13. Ryugu's Parent-Body Processes Estimated from Hayabusa2 Multi-Band Optical Observations

Author: Sugita, S., Honda, R., Morota, T., Kameda, S., Sawada, H., Tatsumi, E., Honda, C., Yokota, Y., Yamada, M., Kouyama, T., Sakatani, N., Suzuki, H., Yoshioka, K., Hayakawa, M., Cho, Y., Matsuoka, M., Hirata, N., Domingue, D. L., Miyamoto, H., Kikuchi, H., Hemmi, R., Michikami, T., Barnouin, O.S., Ernst, C. M., Palmer, E., Gaskell, R., Michel, P., Hirabayashi, M., Jaumann, R, Otto, K., Schroeder, S., Hiroi, T., Nakamura, T., Komatsu, G., Yoshikawa, M., Tanaka, S., Shirai, K., Watanabe, S, Tsuda, Y., Schmitz, N., and Ogawa, K.
Subjects: Planetengeologie, Asteroiden und Kometen, surface boulders, Ryugu, meteorites, Hayabusa2
Published: 2019

14. 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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15. Effects of dust layers on thermal Emission from airless bodies

Author: Biele, Jens, Kuehrt, Ekkehard, Senshu, Hiroki, Sakatani, Naoya, Ogawa, Kazunori, Hamm, Maximilian, Grott, Matthias, Okada, Tatsuaki, and Arai, Takehiko
Subjects: Asteroiden und Kometen, lcsh:QE1-996.5, lcsh:Geography. Anthropology. Recreation, Small bodies, Nutzerzentrum für Weltraumexperimente (MUSC), lcsh:Geology, Surfaces, Dust cover, lcsh:G, Planetenphysik, Thermophysical models, Solar System, Thermal inertia, Layering
Abstract: We have investigated the influence of thin thermally opaque dust layers on the thermal emission of rocks and regolith and determined the thermal response of these dust-covered surfaces to diurnal insolation cycles. Results are computed for Hayabusa2’s target asteroid (162173) Ryugu, which was observed by thermal infrared instruments on the orbiter and in situ. We show that even a very thin (10..100 μm) fine-grained porous dust layer with thermal inertia of 25 J m−2 K−1 s−1/2 can have a significant influence on surface temperatures and alter the apparent thermal inertia of the underlying material derived under the simplified assumption of a homogenous half space by more than 20%. The masking of the underlying material is complete at about 1 diurnal skin depth, corresponding to ~ 10 mm on Ryugu. Between 0.1 and 1 diurnal skin depths, we find a thermal lag smaller than what would be predicted for a surface consisting of dust only. If a dust cover were present on Ryugu, this should be clearly visible in the data returned by the orbiter’s thermal infrared imager (TIR) and the MASCOT lander’s radiometer (MARA), which observed a single boulder at the landing site. However, this appears not to be the case, and dust seems to play a minor role in the thermal emission from the asteroid.
Published: 2019

16. Surface physical properties from HP³ radiometer measurements on the Mars mission InSight

Author: Mueller, N., Grott, M., Piqueux, S., Kopp, E., Spohn, T., Smrekar, S.E., Knollenberg, J., Hudson, T.L., Krause, C., Siegler, M., Spiga, A., Morgan, P., Golombek, M., and Banerdt, W.B.
Subjects: Asteroiden und Kometen, Weltrauminstrumente, Institut für Planetenforschung, Leitungsbereich PF, Mars, Messung, Oberflächentemperatur, Nutzerzentrum für Weltraumexperimente (MUSC)
Published: 2019

17. The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

Author: Axel Hagermann, Yuri Shimaki, Makoto Yoshikawa, Masateru Ishiguro, Osamu Mori, Takehiko Arai, Masahiro Hayakawa, Takahiro Hiroi, Robert Gaskell, Manabu Yamada, Kei Shirai, N. Takaki, Takanao Saiki, Moe Matsuoka, Yuto Takei, Hirotaka Sawada, Naru Hirata, Fuyuto Terui, Yoshiaki Ishihara, Yoshiyuki Tsuda, Seiichi Tazawa, Hiroaki Kamiyoshihara, Ryodo Hemmi, Deborah L. Domingue, Rina Noguchi, Shinsuke Abe, Nicole Schmitz, Masanao Abe, Ralf Jaumann, Satoru Nakazawa, L. Le Corre, Kazuyoshi Asari, Takanobu Shimada, Shogo Tachibana, Yusuke Oki, M. Ozaki, R. Yamada, Katharina A. Otto, Hiroshi Araki, Faith Vilas, S. Oshigami, Toshimichi Otsubo, Patrick Michel, C. Sugimoto, K. Ogawa, Hideaki Kikuchi, Sei-ichiro Watanabe, Hiroki Senshu, Florian Thuillet, Yutaka Suzuki, T. Fukuhara, Sunao Hasegawa, K. Yamamoto, Ronald-Louis Ballouz, Satoshi Tanaka, Naoya Sakatani, Hirohide Demura, Paul A. Abell, Yuya Mimasu, T. G. Müller, Yoshiko Ogawa, Hideaki Miyamoto, Goro Komatsu, Shota Kikuchi, Carolyn M. Ernst, Fumi Yoshida, Olivier S. Barnouin, Eric Palmer, Rie Honda, Tomoki Nakamura, Yasuhiro Yokota, Yuki Takao, Tomohiko Sekiguchi, Kosuke Yoshioka, Shingo Kameda, Satoshi Hosoda, Eri Tatsumi, Kenji Nagata, Hajime Yano, Takahiro Iwata, Stefan Schröder, Yukio Yamamoto, Makoto Taguchi, Tatsuhiro Michikami, Kent Yoshikawa, J. Kimura, H. Suzuki, Seiji Sugita, Noriyuki Namiki, Yuichiro Cho, Go Ono, C. Honda, Hikaru Yabuta, Tomokatsu Morota, Ryudo Tsukizaki, A. Higuchi, Masatoshi Hirabayashi, Masato Okada, T. Takahashi, M. Shizugami, Chikako Hirose, Kazutaka Nishiyama, Takahide Mizuno, Hirotomo Noda, M. A. Barucci, Sho Sasaki, Masaki Fujimoto, Atsushi Fujii, Seiitsu Tsuruta, Tatsuaki Okada, Stefania Soldini, H. Ikeda, Tomohiro Yamaguchi, Michael E. Zolensky, Toru Kouyama, Koji Matsumoto, Naoko Ogawa, Yuichi Iijima, Hiroshi Takeuchi, Institute of Ecology, Tallinn University-Tallinn University, Institute of Space and Astronautical Science (ISAS), Department of Physics, Tokyo, Waseda University, Institute for Research on Earth Evolution [Yokosuka] (IFREE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Institute of Observational Research for Global Change, Department of Applied Physics, The University of Tokyo, University of Electro-Communications [Tokyo] (UEC), Seoul National University [Seoul] (SNU), Tsukuba Space Center (TKSC), Japan Aerospace Exploration Agency [Tokyo] (JAXA), National Institute of Polar Research [Tokyo] (NiPR), Brown University, Service d'hépato-gastro-entérologie [Hôpital Saint-Louis], Groupe Hospitalier Saint Louis - Lariboisière - Fernand Widal [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP), Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, College of Industrial Technology, Nihon University, The Open University [Milton Keynes] (OU), Hiroshima University, Electronic Navigation Research Institute (ENRI), Ministry of Land, Infrastructure, Transport and Tourism, Dept Anim & Dairy Sci, University of Gerogia, National Institute of Agro-Environmental Sciences (NIAES), Mitsubishi Research Institute, Inc., Department of Natural History Sciences, Hokkaido University, Planetary Science Institute [Tucson] (PSI), Sol Agro et hydrosystème Spatialisation (SAS), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Max-Planck-Institut für Sonnensystemforschung (MPS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), GEOMA, Université de Vigo, Universidate de Vigo, Plasma Research Center, University of Tsukuba, IHP Microelctronics, Advanced Materials Institute and Department of Chemistry, Fukuoka University, Department of Applied Mathematics and Physics, Graduate school of Mathematics, Kyoto-Kyoyo University, Department of Environmental and Materials Engineering, Nagoya Institute, Graduate School of Science and Engineering, Tokyo Metropolitan University [Tokyo], Institute of Environmental Systems (SUIKO), Kyushu University [Fukuoka], Graduate School of Science and Technology, Keio University, Rikkyo University [Tokyo], Dept. of Electronics Engineering, University of Electro-Communication, Institute for Sustainable Humanosphere (RISH), Kyoto University [Kyoto], Graduate School of Pharmaceutical Sciences, Tohoku, Tohoku University [Sendai], SolarTerrestrial Environment Laboratory, Nagoya University, Department of Geology and Geophysics, Ministry of Land, Infrastructure, Transport and Tourism (MLIT), Hokkaido University [Sapporo, Japan], DLR Institute of Planetary Research, German Aerospace Center (DLR), 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), Universidade de Vigo, Department of Advanced Technology and Development, BML, Matoba, Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Department of Physics, University of California [Irvine] (UCI), University of California-University of California, Biomécanique et génie biomédical (BIM), Centre National de la Recherche Scientifique (CNRS), University of Alaska [Fairbanks] (UAF), Information Science Laboratory, Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, Department of Earth and Planetary Sciences [Kobe], Kobe University, ANR: 15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), The University of Tokyo (UTokyo), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), and ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015)
Subjects: Asteroiden und Kometen, Physics, Multidisciplinary, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Stereochemistry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Article, Planetengeologie, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Ryugu, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: 著者人数: 120名(所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 澤田, 弘崇; 横田, 康弘; 坂谷, 尚哉; 岡田, 達明; 田中, 智; 飯島, 祐一; 早川, 雅彦; 松岡, 萌; R.-L. Ballouz; 嶌生, 有理; 水野, 貴秀; 石原, 吉明; 長谷川, 直; 藤本, 正樹; 吉川, 真; 山本, 幸生; 白井, 慶; R. Noguchi; 尾川, 順子; 照井, 冬人; 菊地, 翔太; 山口, 智宏; 竹内, 央, 三桝, 裕也; 高橋, 忠輝; 竹井, 洋; 藤井, 淳; 中澤, 暁; 細田, 聡史; 森, 治; 嶋田, 貴信; Soldini, Stefania; 岩田, 隆浩; 安部, 正真; 矢野, 創; 月崎, 竜童; 尾崎, 正伸; 西山, 和孝; 佐伯, 孝尚; 渡邊, 誠一郎; 津田, 雄一), Accepted: 2019-03-12, 資料番号: SA1180387000
Published: 2019
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18. Solar Sails for Planetary Defense & High-Energy Missions

Author: Waldemar Bauer, Tobias Mikschl, Kai Borchers, Siebo Reershemius, Michael Ruffer, Dominik Quantius, Sergio Montenegro, Federico Cordero, Friederike Wolff, David Hercik, Simon Tardivel, Norbert Toth, Christian Ziach, Ralf Boden, Tom Spröwitz, Maciej Sznajder, Matteo Ceriotti, Christian Grimm, Johannes Riemann, Etienne Dumont, Jens Biele, Nicole Schmitz, Patric Seefeldt, Ivanka Pelivan, Jan-Gerd Mess, Kaname Sasaki, Rico Jahnke, Elisabet Wejmo, Tra-Mi Ho, Alexander Koncz, Aaron Koch, Thomas Renger, Colin R. McInnes, Bernd Dachwald, Jan Thimo Grundmann, Peter Spietz, Eugen Mikulz, Christian Krause, Volker Maiwald, Alessandro Peloni, Roy Lichtenheldt, Wolfgang Seboldt, and Caroline Lange
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Computer science, Systemanalyse Raumtransport, Space weather, multiple NEA rendezvous, 01 natural sciences, MASCOT2, law.invention, Jupiter, Orbiter, law, 0103 physical sciences, Aerospace engineering, solar sail, 010303 astronomy & astrophysics, planetary defense, 0105 earth and related environmental sciences, Gossamer-1, Raumfahrt-Systemdynamik, Spacecraft, Payload, business.industry, MASCOT, Rendezvous, Systementwicklung und Projektbüro, Solar sail, Systemanalyse Raumsegment, Nutzerzentrum für Weltraumexperimente (MUSC), small spacecraft, Planetengeologie, Orbit, Asteroid, nanolander, Avioniksysteme, Polar, Land und Explorationstechnologie, Planetare Sensorsysteme, business, Mechanik und Thermalsysteme
Abstract: 20 years after the successful ground deployment test of a (20 m)2 solar sail at DLR Cologne, and in the light of the upcoming U.S. NEAscout mission, we provide an overview of the progress made since in our mission and hardware design studies as well as the hardware built in the course of our solar sail technology development. We outline the most likely and most efficient routes to develop solar sails for useful missions in science and applications, based on our developed ‘now-term’ and near-term hardware as well as the many practical and managerial lessons learned from the DLR-ESTEC Gossamer Roadmap. Mission types directly applicable to planetary defense include single and Multiple NEA Rendezvous ((M)NR) for precursor, monitoring and follow-up scenarios as well as sail-propelled head-on retrograde kinetic impactors (RKI) for mitigation. Other mission types such as the Displaced L1 (DL1) space weather advance warning and monitoring or Solar Polar Orbiter (SPO) types demonstrate the capability of near-term solar sails to achieve asteroid rendezvous in any kind of orbit, from Earth-coorbital to extremely inclined and even retrograde orbits. Some of these mission types such as SPO, (M)NR and RKI include separable payloads. For one-way access to the asteroid surface, nanolanders like MASCOT are an ideal match for solar sails in micro-spacecraft format, i.e. in launch configurations compatible with ESPA and ASAP secondary payload platforms. Larger landers similar to the JAXA-DLR study of a Jupiter Trojan asteroid lander for the OKEANOS mission can shuttle from the sail to the asteroids visited and enable multiple NEA sample-return missions. The high impact velocities and re-try capability achieved by the RKI mission type on a final orbit identical to the target asteroid's but retrograde to its motion enables small spacecraft size impactors to carry sufficient kinetic energy for deflection.
Published: 2019

19. HP³ Radiometer Measurements from the Mars Mission InSight

Author: Mueller, N., Grott, M., Piqueux, S., Kopp, Emanuel, Spohn, T., Smrekar, S.E., Knollenberg, J., Hudson, T.L., Krause, C., Plesa, A.-C., Siegler, M.A., Spiga, Aymeric, Forget, F., Millour, E., Morgan, P., Golombek, M., and Banerdt, W.B.
Subjects: Asteroiden und Kometen, Weltrauminstrumente, Planetenphysik, Leitungsbereich PF, Mars, Messung, Oberflächentemperatur, Nutzerzentrum für Weltraumexperimente (MUSC)
Published: 2019

20. Comparison of Morphological Parameters of Boulders Larger Than 1m on Ryugu and 67P

Author: Vincent, J.-B., Jaumann, R., Schmitz, Nicole, and Schröder, Stefan
Subjects: Asteroiden und Kometen, Planetengeologie, asteroids, Hayabusa 2, 67P, Rosetta, Ryugu, comets
Published: 2019

21. Spatial Distribution an Morphology of Craters on Ryugu: Implications for Surface Processes on the C-Type Asteroid

Author: Cho, Y., Morota, T., Kanamaru, M., Ernst, C. M., Barnouin, Olivier S., Tatsumi, E., Hirabayashi, M., Otto, Katharina A., Schmitz, Nicole, Wagner, Roland, Jaumann, Ralf, Miyamoto, H., Kikuchi, H., Hemmi, R., Honda, R., Kameda, S., Yokota, Y., Kouyama, Toru, Suzuki, H., Yamada, M., Sakatani, N., Honda, C., Hayakawa, M., Yoshioka, K., Matsuoka, Moe, Michikami, T., Hirata, N., Sawada, H., and Sugita, Seiji
Subjects: Planetengeologie, Asteroiden und Kometen, Craters, asteroid, morphology, Ryugu, surface processes, Hayabusa2, ONC
Published: 2019

22. In-Situ Determination of Thermal Inertia on Near Earth Asteroid (162173) Ryugu using MARA - The MASCOT Radiometer

Author: Grott, Matthias, Knollenberg, Jörg, Hamm, Maximilian, Ogawa, Kazunori, Jaumann, R., Otto, Katharina A., Matz, K-D, Schmitz, Nicole, Koncz, Alexander, Trauthan, Frank, Senshu, Hiroki, Sakatani, N., Tanaka, Satoshi, Arai, T., Mottola, Stefano, Pelivan, Ivanka, Drube, Line, Vincent, Jean-Baptiste, Delbo, M, Michel, P., Yano, H., Pilorget, C., Schlotterer, Markus, Krause, Christian, Ho, Tra-Mi, and Moussi-Soffys, A.
Subjects: Asteroiden und Kometen, Planetenphysik, Thermische Trägheit, Land und Explorationstechnologie, Ryugu, Systementwicklung und Projektbüro, Navigations- und Regelungssysteme
Published: 2019

23. The Heat Flow and Physical Properties Package HP3 on InSight - First Results

Author: Spohn, Tilman, Grott, Matthias, Smrekar, S., Knollenberg, Jörg, Hudson, T.L., Krause, Christian, Müller, Nils, Wippermann, Torben, Krömer, Olaf, Lichtenheldt, Roy, Wiśniewski, Lukasz, Grygorczuk, J., Reershemius, Siebo, Spröwitz, Tom, Scharringhausen, Marco, Kopp, Emanuel, Morgan, P., Plesa, Ana-Catalina, Breuer, Doris, and Hagermann, A.
Subjects: Asteroiden und Kometen, Raumfahrt-Systemdynamik, Weltrauminstrumente, Planetenphysik, HP3, Mars, Land und Explorationstechnologie, Heat Flow, InSight, Nutzerzentrum für Weltraumexperimente (MUSC)
Published: 2019

24. The Evolution of Ryugu's Parent Body Constrained by Hayabusa2 Imaging Observations

Author: Sugita, S., Honda, R., Kameda, S., Honda, C., Yokota, Y., Yamada, M., Kouyama, T., Sakatani, N., Suzuki, H., Yoshioka, K., Cho, Y., Matsuoka, M., Ogawa, K., Domingue, D.L., Miyamoto, H., Barnouin, O.S., Michel, P., Ernst, C. M., Hiroi, T., Nakamura, T., Sawada, H., Hayakawa, M., Hirata, N., Kikuchi, H., Hemmi, R., Michikami, T., Palmer, E., Gaskell, R., Hirabayashi, M., Jaumann, R, Otto, K., Schmitz, N., Schröder, S.E., Komatsu, G., Tanaka, S., Shirai, K., Yoshikawa, M., Watanabe, S, and Tsuda, Y.
Subjects: Planetengeologie, Asteroiden und Kometen, Ryugu, Hayabusa2
Published: 2019

25. Generation of photoclinometric DTMs for application to transient changes on the surface of comet 67P/Churyumov-Gerasimenko

Author: J.-B. Vincent, R. L. Kirk, Y. Tang, S. P. D. Birch, S. Squyres, N. W. Kutsop, and A. G. Hayes
Subjects: Physics, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comets: individual: 67P/Churyumov-Gerasimenko – Methods: data analysis – Techniques: image processing, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Transient (oscillation), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Context. The wide spatial and temporal coverage of 67P/Churyumov-Gerasimenko (67P) by the Rosetta mission has revealed a surface created by scattered large-scale changes and numerous small-scale changes. The many small-scale changes are of particular interest because they are unexpected and ubiquitous. As their topographic relief is often smaller than one meter, which is below the resolution of any shape models, we need higher resolution topography to analyze them properly. Aims. We describe a photoclinometry method that is able to retrieve surface elevations for a single OSIRIS image of the surface of 67P. With this method, we can provide accurate measures, along with error estimates, of the centimeter-scale topography of observed transient changes. Methods. Photoclinometry, or shape-from-shading, estimates heights by examining the light reflection of the surface as dictated by a photometric model under a specified set of viewing geometries. Assuming a standard photometric model for 67P, we can recreate the shading of a surface under specified viewing geometries. The output is a high-resolution height map that matches the original image pixel by pixel. We then provide estimates of the error in the retrieved heights and ensure that our method is valid with a series of checks. Results. We generate digital terrain models (DTMs) with a vertical resolution comparable to or smaller than the pixel scale. This allows us to accurately measure changes in the surface topography on centimeter scales. We find that most changes within the smooth terrains involve the transport or removal of material thinner than one meter.
Published: 2019

26. Small Scale Surface Roughness of Ryugu

Author: Otto, Katharina A., Parekh, Rutu, Matz, K-D, Jaumann, R, Krohn, Katrin, Stephan, Katrin, Schmitz, Nicole, Ho, Tra-Mi, Elgner, Stephan, Hamm, Maximilian, Honda, Rie, Kameda, Shingo, Preusker, Frank, Scholten, Frank, Schröder, Stefan, Senshu, Hiroki, Sugita, Seiji, and Trauthan, Frank
Subjects: Planetengeologie, Asteroiden und Kometen, Planetenphysik, Planetengeodäsie, Surface Structure, Systementwicklung und Projektbüro, Asteroid Ryugu, Roughness, Regolith
Published: 2019

27. The Dependence of Spectral Features on Ice Content and Temperature for Vesta and Ryugu

Author: Michalik, Tanja, Maturilli, Alessandro, Otto, Katharina A., Schmitt, B., Poch, O., Beck, P., and Helbert, Jörn
Subjects: Hayabusa 2, Asteroiden und Kometen, Vesta, Spectral, Ice, Leitungsbereich PF, Ryugu, sublimation, Asteroids, Dawn
Published: 2019

28. Studying the boulder morphology on comet 67P using discrete element simulations

Author: Sachse, Manuel, Kappel, David, Haack, David, and Otto, Katharina A.
Subjects: Asteroiden und Kometen, boulders, discrete element simulations, 67P, cliffs
Abstract: Our overall aim is to investigate the physics of volatile-related surface features on asteroids and comets. In the present work, we focus on studying the morphology of boulders and cliff collapses on comet 67P/Churyumov-Gerasimenko’s surface (Fig. 1). This study continues and complements previous work, where we have been investigating dynamical processes that are implied by surface features on comet 67P [1] and on asteroid Vesta[2].
Published: 2019

29. Imaging Inclusion Spectral Diversity in Carbonaceous Chondrites with MASCam

Author: Schröder, Stefan, Otto, Katharina A., Schmitz, Nicole, Scharf, Hannah, Greshake, Ansgar, Scholten, Frank, Trauthan, Frank, and Jaumann, Ralf
Subjects: Planetengeologie, Asteroiden und Kometen, MasCam, Inclusions, Planetengeodäsie, Asteroid Ryugu, Laboratory experiment, Carbonaceous Chondrites, Regolith, meteorites
Published: 2019

30. Discrete Element Simulations of Test Scenarios for Studying Landslides on Asteroids

Author: Sachse, Manuel, Kappel, David, Haack, David, and Otto, Katharina A.
Subjects: Asteroiden und Kometen, asteroids, landslides, 67P, discrete element method
Published: 2019

31. 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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32. Spectral Properties of Ceres' Bluish Material — Comparison with Terrestrial Impact Melt

Author: Stephan, Katrin, Jaumann, R, McFadden, L., Haack, David, Krohn, Katrin, Otto, Katharina A., Wagner, Roland, and Hiesinger, H.
Subjects: Planetengeologie, Asteroiden und Kometen, Dawn Ceres Impaktkrater
Published: 2019

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

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

Author: D. Bodewits, Lyn R. Doose, Giovanna Rinaldi, U. Fink, M. De Cecco, Ivano Bertini, Marco Fulle, Maria Teresa Capria, Anny Chantal Levasseur-Regourd, D. Bockelée-Morvan, Imre Toth, Luisa Lara, Sonia Fornasier, H. Krueger, Mauro Ciarniello, Vladimir E. Zakharov, Holger Sierks, Alessandra Migliorini, Gabriele Arnold, Andrea Longobardo, Carsten Güttler, X. Hu, Michelangelo Formisano, Francesco Marzari, Xian Shi, Wing-Huen Ip, Philippe Lamy, F. La Forgia, Stefano Mottola, Gabriele Cremonese, Detlef Koschny, Zhong-Yi Lin, David Kappel, Raphael Marschall, Fredric W. Taylor, V. Da Deppo, S. Ivanovski, J. J. López-Moreno, Fabrizio Capaccioni, Gianrico Filacchione, H. U. Keller, Stéphane Erard, M. C. De Sanctis, Jean-Loup Bertaux, J. Deller, Pedro J. Gutiérrez, Stefano Debei, R. Rodrigo, Jacques Crovisier, Giampiero Naletto, Björn Davidsson, Cecilia Tubiana, M. A. Barucci, Colin Snodgrass, Monica Lazzarin, Ludmilla Kolokolova, Agenzia Spaziale Italiana, German Research Foundation, Centre National de la Recherche Scientifique (France), Ministerio de Economía y Competitividad (España), Government of Sweden, European Space Agency, l'Observatoire de Paris, Science and Technology Facilities Council (UK), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin (TU), International Space Science Institute [Bern] (ISSI), INAF - Osservatorio Astronomico di Trieste (OAT), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Physik und Astrophysik [Potsdam], Universität Potsdam, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Universita degli studi di Napoli 'Parthenope' [Napoli], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Oxford], University of Oxford [Oxford], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Technische Universität Berlin (TUB), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Comet, Comets, Data analysis, General, Individual, Methods, FOS: Physical sciences, Coma (optics), Spatial distribution, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Methods: data analysis, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, data analysis [methods], ddc:530, 010303 astronomy & astrophysics, Southern Hemisphere, Comet: individual: 67P/Churyumov-Gerasimenko, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Diurnal temperature variation, Leitungsbereich PF, comets: individual: 67P/Churyumov-Gerasimenko, Institut für Physik und Astronomie, general [Comets], Astronomy and Astrophysics, Comets: general, 13. Climate action, Space and Planetary Science, astro-ph.EP, Environmental science, Spatial variability, Longitude, Astrophysics - Earth and Planetary Astrophysics
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet.© C. Tubiana et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Daten-technik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. VIRTIS was built by a consortium, which includes Italy, France, and Germany, under the scientific responsibility of the Istituto di Astrofisica e Planetologia Spaziali of INAF, Italy, which also guides the scientific operations. The VIRTIS instrument development, led by the prime contractor Leonardo-Finmeccanica (Florence, Italy), has been funded and managed by ASI, with contributions from Observatoire de Meudon financed by CNES, and from DLR. We thank the Rosetta Science Ground Segment and the Rosetta Mission Operations Centre for their support throughout all the phases of the mission. The VIRTIS calibrated data will be available through the ESA's Planetary Science Archive Website (www.rssd.esa.int) and is available upon request until posted to the archive. We thank the following institutions and agencies for support of this work: Italian Space Agency (ASI, Italy) contract number I/024/12/1, Centre National d'Etudes Spatiales (CNES, France), DLR (Germany), NASA (USA) Rosetta Program, and Science and Technology Facilities Council (UK).
Published: 2019
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35. 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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36. Spectral properties of H2O ice depending on particle size and surface temperature – comparison between laboratory data and icy satellites observations

Author: Stephan, Katrin, Ciarniello, Mauro, Dalle Ore, C. M., Cruikshank, D P, Filacchione, G., Haack, David, Jaumann, R., Poch, O., Raponi, A, and Istigomah, I
Subjects: Planetengeologie, Asteroiden und Kometen, Eis Laborspektroskopie
Published: 2019

37. Surface Thermophysical Properties of Near Earth Asteroid (162173) Ryugu from in-situ Observations: First Results from the MASCOT MARA Radiometer

Author: Grott, Matthias, Knollenberg, Jörg, Hamm, Maximilian, Ogawa, Kazunori, Jaumann, R, Otto, Katharina A., Matz, K-D, Schmitz, Nicole (Admin.), Funktional, Koncz, Alexander, Trauthan, Frank, Senshu, H., Okada, T., Kührt, Ekkehard, Biele, Jens, Neumann, Wladimir, Knapmeyer, Martin, Helbert, Jörn, Maturilli, Alessandro, Müller, Nils, and Hagermann, A.
Subjects: Asteroiden und Kometen, Planetengeologie, Planetenphysik, MASCOT, Ryugu, MARA, Nutzerzentrum für Weltraumexperimente (MUSC), Asteroiden
Published: 2019

38. VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation

Author: Stéphane Erard, Pierre Drossart, Mauro Ciarniello, Gabriele Arnold, M. T. Capria, David Kappel, Giovanna Rinaldi, Andrea Longobardo, F. Andrieu, Fabrizio Capaccioni, J. Crovisier, Fredric W. Taylor, Pedro Hasselmann, M. C. De Sanctis, Dominique Bockelée-Morvan, C. Leyrat, Gianrico Filacchione, 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), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), DLR Institut für Planetenforschung, University of Oxford [Oxford], and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, Coma (optics), Astrophysics, Color temperature, 01 natural sciences, comets: individual: 67P, Phase (matter), 0103 physical sciences, infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Churyumov-Gerasimenko, Physics, [PHYS]Physics [physics], comets: general, Spectral properties, Leitungsbereich PF, Elevation, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We analyze 2–5μm spectroscopic observations of the dust coma of comet 67P/Churyumov-Gerasimenko obtained with the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-H) instrument on board Rosetta from 3 June to 29 October 2015 at heliocentric distancesrh= 1.24–1.55 AU. The 2–2.5μm color, bolometric albedo, and color temperature were measured using spectral fitting. Data obtained atα= 90° solar phase angle show an increase in bolometric albedo (0.05–0.14) with increasing altitude (0.5–8 km), accompanied by a possible marginal decrease in color and color temperature. Possible explanations include dark particles on ballistic trajectories in the inner coma and radial changes in particle composition. In the phase angle range 50°–120°, phase reddening is significant (0.031%/100 nm deg−1) for a mean color of 2%/100 nm atα= 90°, which might be related to the roughness of the dust particles. Moreover, a decrease in color temperature with decreasing phase angle is also observed at a rate of ~0.3 K deg−1, consistent with the presence of large porous particles, with low thermal inertia, and showing a significant day-to-night temperature contrast. Comparing data acquired at fixed phase angle (α= 90°), a 20% increase in bolometric albedo is observed near perihelion. Heliocentric variations in dust color are not significant in the time period we analyzed. The measured color temperatures vary from 260 to 320 K, and follow arh−0.6variation in therh= 1.24–1.5 AU range, which is close to the expectedrh−0.5value.
Published: 2019
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39. Linking surface morphology, composition, and activity on the nucleus of 67P/Churyumov-Gerasimenko

Author: Jessica Agarwal, J. Deller, Pedro J. Gutiérrez, R. Rodrigo, Monica Lazzarin, Gabriele Cremonese, Holger Sierks, J. D. P. Deshapriya, Stefano Debei, D. Bodewits, Björn Davidsson, Cecilia Tubiana, Imre Toth, Pedro Hasselmann, Giampiero Naletto, Marco Fulle, Sabrina Ferrari, M. A. Barucci, Sonia Fornasier, Carsten Güttler, J. J. Lopez Moreno, Wing-Huen Ip, Philippe Lamy, Cesare Barbieri, Jean-Loup Bertaux, M. De Cecco, F. La Forgia, M. Küppers, Z. Y. Lin, Maurizio Pajola, M. L. Lara, Ivano Bertini, H. U. Keller, V. Da Deppo, Francesco Marzari, C. Feller, Van H. Hoang, Detlef Koschny, Xian Shi, Stefano Mottola, 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), Institute of Physics [Hanoi], Vietnam Academy of Science and Technology (VAST), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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), 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 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 Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), 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], European Space Astronomy Centre (ESAC), European Space Agency (ESA), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), 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), Technische Universität Braunschweig [Braunschweig], ITA, USA, GBR, FRA, DEU, Federal Ministry of Education and Research (Germany), Agence Nationale de la Recherche (France), Agenzia Spaziale Italiana, Ministerio de Ciencia, Innovación y Universidades (España), and Government of Sweden
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet, observational [methods], Data analysis, FOS: Physical sciences, Coma (optics), Individual, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Photometric, 01 natural sciences, photometric [techniques], techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], Comet nucleus, 0103 physical sciences, medicine, data analysis [methods], Comets, Methods, 010303 astronomy & astrophysics, Observational, Optical depth, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Techniques, Resolution (electron density), Astronomy and Astrophysics, methods: data analysis, Plume, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis – methods: observational – techniques: photometric, Radiance, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., The Rosetta space probe accompanied comet 67P/Churyumov-Gerasimenko for more than two years, obtaining an unprecedented amount of unique data of the comet nucleus and inner coma. This has enabled us to study its activity almost continuously from 4 au inbound to 3.6 au outbound, including the perihelion passage at 1.24 au. This work focuses identifying the source regions of faint jets and outbursts and on studying the spectrophotometric properties of some outbursts. We use observations acquired with the OSIRIS/NAC camera during July-October 2015, that is, close to perihelion. Methods. We analyzed more than 2000 images from NAC color sequences acquired with 7-11 filters covering the 250-1000 nm wavelength range. The OSIRIS images were processed with the OSIRIS standard pipeline up to level 3, that is, converted in radiance factor, then corrected for the illumination conditions. For each color sequence, color cubes were produced by stacking registered and illumination-corrected images. Results. More than 200 jets of different intensities were identified directly on the nucleus. Some of the more intense outbursts appear spectrally bluer than the comet dark terrain in the visible-to-near-infrared region. We attribute this spectral behavior to icy grains mixed with the ejected dust. Some of the jets have an extremely short lifetime. They appear on the cometary surface during the color sequence observations, and vanish in less than some few minutes after reaching their peak. We also report a resolved dust plume observed in May 2016 at a resolution of 55 cm pixel(-1), which allowed us to estimate an optical depth of similar to 0.65 and an ejected mass of similar to 2200 kg, assuming a grain bulk density of similar to 800 kg m(-3). We present the results on the location, duration, and colors of active sources on the nucleus of 67P from the medium-resolution (i.e., 6-10 m pixel(-1)) images acquired close to perihelion passage. The observed jets are mainly located close to boundaries between different morphological regions. Some of these active areas were observed and investigated at higher resolution (up to a few decimeter per pixel) during the last months of operations of the Rosetta mission. Conclusions. These observations allow us to investigate the link between morphology, composition, and activity of cometary nuclei. Jets depart not only from cliffs, but also from smooth and dust-covered areas, from fractures, pits, or cavities that cast shadows and favor the recondensation of volatiles. This study shows that faint jets or outbursts continuously contribute to the cometary activity close to perihelion passage, and that these events are triggered by illumination conditions. Faint jets or outbursts are not associated with a particular terrain type or morphology.© S. Fornasier et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Goettingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, the Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. S.F. acknowledges the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004). The authors thank H. Campins for his comments that helped us improve this article. The authors would like to thank Andrew Cooper and Marco Parigi for spotting the inconsistencies in regional boundaried of Fig. 1 in the online preprint version of the paper.
Published: 2019
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40. Comparison of Inclusion Size Frequency Distributions of Rocks on Ryugu and Carbonaceous Chondrites

Author: Otto, Katharina A., Greshake, A., Scharf, Hannah, Schmitz, Nicole, Schröder, Stefan, Stephan, Katrin, Trauthan, Frank, Elgner, Stephan, Matz, K-D, Preusker, Frank, Scholten, Frank, and Jaumann, Ralf
Subjects: Mascam, Asteroiden und Kometen, Planetengeologie, Planetengeodäsie, Asteroid Ryugu, Mascot, Carbonaceous Chondrites, Regolith, Comparative Imagery
Published: 2019

41. Ryugu as seen close up by MASCOT

Author: Schröder, Stefan, Jaumann, Ralf, Schmitz, Nicole, Otto, Katharina A., Stephan, Katrin, Preusker, Frank, Elgner, Stephan, Matz, K.-D., Roatsch, Thomas, Parekh, Rutu, Mottola, Stefano, Krohn, Katrin, Trauthan, Frank, Koncz, Alexander, Michaelis, Harald, Neumann, Wladimir, Vincent, Jean-Baptiste, Wagner, Roland, and Sugita, Seiji
Subjects: Planetengeologie, Asteroiden und Kometen, Ryugu, Planetare Sensorsysteme
Abstract: In October 2018, MASCOT landed on the surface of Ryugu to start a campaign of in-situ measurements. Its brief mission was successful, with the onboard camera revealing the surface of this C-type asteroid in unpre- cedented detail. The presence of abundant mm-sized, multi-colored inclusions in one rock suggests a link between Ryugu and carbonaceous chondrites.
Published: 2019

42. Morphology and measurement of fractal dimension of boulders on Ryugu

Author: Parekh, R., Jaumann, R., Schmitz, N., Schröder, S., Otto, K., Krohn, K., Stephan, K., Matz, K-D, Wagner, Roland, Elgner, S., Preusker, F., Scholten, F., Roatsch, Thomas, Trauthan, F., Koncz, A., and Ho, Tra-Mi
Subjects: Planetengeologie, Asteroiden und Kometen, MASCOT, Boulders, Planetengeodäsie, Planetare Sensorsysteme, Systementwicklung und Projektbüro, Ryugu, Fractal dimension
Published: 2019

43. High-resolution Surface Structures of Asteroid Ryugu Derived from MasCam Observations

Author: Otto, Katharina A., Parekh, Rutu, Matz, K-D, Jaumann, R, Schröder, Stefan, Schmitz, Nicole, Ho, Tra-Mi, Elgner, Stephan, Hamm, Maximilian, Honda, Rie, Kameda, Shingo, Krohn, Katrin, Scholten, Frank, Senshu, Hiroki, Stephan, Katrin, Sugita, Seiji, and Trauthan, Frank
Subjects: Asteroiden und Kometen, Planetengeologie, Planetenphysik, Planetengeodäsie, Surface Structure, Systementwicklung und Projektbüro, Asteroid Ryugu, Roughness, Regolith
Abstract: Using high resolution imagery from C-type asteroid Ryugu collected by MASCOT, we derive measures for surface roughness from digital image analysis.
Published: 2019

44. Synthesis of the morphological description of cometary dust at comet 67P/Churyumov-Gerasimenko

Author: Martin Hilchenbach, Klaus Hornung, Alberto Flandes, Jérémie Lasue, Anny Chantal Levasseur-Regourd, Giovanna Rinaldi, Stavro Ivanovski, Marco Fulle, Harald Krüger, Andrea Longobardo, Dominique Bockelée-Morvan, Dennis Bodewits, Stefano Mottola, Yves Langevin, C. Güttler, Gianrico Filacchione, Ivano Bertini, G. P. Tozzi, Holger Sierks, Jürgen Blum, J. Agarwal, Fabrizio Capaccioni, Giampiero Naletto, Thurid Mannel, F. Moreno, Alessandra Rotundi, Imre Tóth, Sihane Merouane, V. Della Corte, John Paquette, Cecilia Tubiana, Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Max-Planck-Institut für Sonnensystemforschung (MPS), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Institute of Physics [Graz], Karl-Franzens-Universität [Graz, Autriche], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astronomico di Trieste (OAT), 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), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Milano] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astrofisico di Arcetri (OAA), Universität der Bundeswehr München [Neubiberg], Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Karl-Franzens-Universität Graz, Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), University of Graz, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Technische Universität Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ITA, FRA, DEU, and ESP
Subjects: Asteroiden und Kometen, instruments [space vehicles], 010504 meteorology & atmospheric sciences, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – space vehicles: instruments, Computer science, Comet, Individual, 01 natural sciences, Space exploration, Astrobiology, Interplanetary dust cloud, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, 67P/Churyumov-Gerasimenko - space vehicles, Comets, General - comets, Instruments, Instrumentation (computer programming), space vehicles: instruments, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Astronomy and Astrophysics, Common framework, Comets: general, [SDU]Sciences of the Universe [physics], Space and Planetary Science
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., Before Rosetta, the space missions Giotto and Stardust shaped our view on cometary dust, supported by plentiful data from Earth based observations and interplanetary dust particles collected in the Earth's atmosphere. The Rosetta mission at comet 67P/Churyumov-Gerasimenko was equipped with a multitude of instruments designed to study cometary dust. While an abundant amount of data was presented in several individual papers, many focused on a dedicated measurement or topic. Different instruments, methods, and data sources provide different measurement parameters and potentially introduce different biases. This can be an advantage if the complementary aspect of such a complex data set can be exploited. However, it also poses a challenge in the comparison of results in the first place. The aim of this work therefore is to summarize dust results from Rosetta and before. We establish a simple classification as a common framework for intercomparison. This classification is based on the dust particle structure, porosity, and strength and also on its size. Depending on the instrumentation, these are not direct measurement parameters, but we chose them because they were the most reliable for deriving our model. The proposed classification has proved helpful in the Rosetta dust community, and we offer it here also for a broader context. In this manner, we hope to better identify synergies between different instruments and methods in the future.© C. Güttler et al. 2019
Published: 2019
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45. Comet 67P/Churyumov-Gerasimenko rotation changes derived from sublimation induced torques

Author: Tobias Kramer, Matthias Läuter, Stubbe F. Hviid, Laurent Jorda, H. U. Keller, Ekkehard Kührt, 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: Insolation, Rotation period, Asteroiden und Kometen, Angular momentum, Inertial frame of reference, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, 01 natural sciences, methods: analytical, 0103 physical sciences, 67P/Churyumov-Gerasimenko Comets Rosetta Rotation Activity, Torque, 010303 astronomy & astrophysics, Fourier series, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Computational physics, On board, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: (Context) The change of the rotation period and the orientation of the rotation axis of comet 67P/Churyumov-Gerasimenko (67P/C-G) is deducible from images taken by the scientific imaging instruments on-board the Rosetta mission with high precision. Non gravitational forces are a natural explanation for these data. (Aims) We describe observed changes for the orientation of the rotation axis and the rotation period of 67P/C-G. For these changes we give an explanation based on a sublimation model with a best-fit for the surface active fraction (model P). Torque effects of periodically changing gas emissions on the surface are considered. (Methods) We solve the equation of state for the angular momentum in the inertial and the body-fixed frames and provide an analytic theory of the rotation changes in terms of Fourier coefficients, generally applicable to periodically forced rigid body dynamics. (Results) The torque induced changes of the rotation state constrain the physical properties of the surface, the sublimation rate and the local active fraction of the surface. (Conclusions) We determine a distribution of the local surface active fraction in agreement with the rotation properties, period and orientation, of 67P/C-G. The torque movement confirms that the sublimation increases faster than the insolation towards perihelion. The derived relatively uniform activity pattern is discussed in terms of related surface features., 11 pages
Published: 2018
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46. Ring-mold craters within Occator Crater, Ceres: evidence for subsurface ice reservoirs

Author: Krohn, Katrin, Jaumann, R., Neesemann, Adrian, Otto, Katharina A., Stephan, Katrin, Wagner, Roland, Tosi, F., Zambon, F., Ruesch, Ottaviano, Williams, D.A., Raymond, C.A., and Russell, C.T.
Subjects: Planetengeologie, Asteroiden und Kometen, asteroids, water-ice, cryovolcanism, crater Formation, small bodies
Published: 2018

47. Ceres' opposition effect observed by the Dawn framing camera

Author: Stefano Mottola, Mauro Ciarniello, Jian-Yang Li, Carol A. Polanskey, Marc D. Rayman, Andrea Longobardo, Lucy A. McFadden, Christopher T. Russell, Steven P. Joy, Julie Castillo-Rogez, Mark V. Sykes, Stefan Schröder, Uri Carsenty, R. Jaumann, Carol A. Raymond, ITA, USA, and DEU
Subjects: Physics, Asteroiden und Kometen, Earth and Planetary Astrophysics (astro-ph.EP), Brightness, Framing (visual arts), 010504 meteorology & atmospheric sciences, asteroids: individual: Ceres – Radiative transfer, Dwarf planet, Minor planets, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Planetengeologie, Wavelength, Impact crater, Space and Planetary Science, Asteroid, 0103 physical sciences, Radiative transfer, Ejecta, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: The surface reflectance of planetary regoliths may increase dramatically towards zero phase angle, a phenomenon known as the opposition effect (OE). Two physical processes that are thought to be the dominant contributors to the brightness surge are shadow hiding (SH) and coherent backscatter (CB). The occurrence of shadow hiding in planetary regoliths is self-evident, but it has proved difficult to unambiguously demonstrate CB from remote sensing observations. One prediction of CB theory is the wavelength dependence of the OE angular width. The Dawn spacecraft observed the OE on the surface of dwarf planet Ceres. We characterize the OE over the resolved surface, including the bright Cerealia Facula, and to find evidence for SH and/or CB. We analyze images of the Dawn framing camera by means of photometric modeling of the phase curve. We find that the OE of most of the investigated surface has very similar characteristics, with an enhancement factor of 1.4 and a FWHM of 3{\deg} (broad OE). A notable exception are the fresh ejecta of the Azacca crater, which display a very narrow brightness enhancement that is restricted to phase angles $< 0.5${\deg} (narrow OE); suggestively, this is in the range in which CB is thought to dominate. We do not find a wavelength dependence for the width of the broad OE, and lack the data to investigate the dependence for the narrow OE. The prediction of a wavelength-dependent CB width is rather ambiguous. The zero-phase observations allow us to determine Ceres' visible geometric albedo as $p_V = 0.094 \pm 0.005$. A comparison with other asteroids suggests that Ceres' broad OE is typical for an asteroid of its spectral type, with characteristics that are primarily linked to surface albedo. Our analysis suggests that CB may occur on the dark surface of Ceres in a highly localized fashion., Comment: Credit: Schr\"oder et al, A&A in press, 2018, reproduced with permission, \copyright ESO
Published: 2018

48. Organic features in the spectrum of 67P/ Churyumov-Gerasimenko from the improved calibration of VIRTIS-M-IR

Author: Raponi, A., Ciarniello, M., Filacchione, G., Capaccioni, F., Desanctis, M.C., Moroz, Liubov, Vinogradoff, V., Tosi, F., Arnold, Gabriele, Quirico, E., Mennella, V., Beck, P., Pilorget, C., Pommerol, Antoine, Schröder, Stefan, Kappel, David, Istiqomah, Istiqomah, Rousseau, Batiste, and Poch, O.
Subjects: Asteroiden und Kometen, Planetengeologie, Rosetta, Calibration, Leitungsbereich PF, Astrophysics::Instrumentation and Methods for Astrophysics, Comet 67P, Astrophysics::Earth and Planetary Astrophysics, VIRTIS, Astrophysics::Galaxy Astrophysics, Composition
Abstract: The VIRTIS spectra of 67P/CG in the region between 2.9 and 3.5 micron display a wide absorption band, which has been associated to the presence of organic compounds. However, several instrumental effects have hindered, so far, the detailed interpretation of the molecules and compounds contributing to this band. In this work we revised the in-flight calibration of the VIRTIS-M-IR instrument onboard Rosetta spacecraft with the aim to improve: a) the detection of low-contrast spectral features and b) the radiometric accuracy. This updated calibration involves all 432 spectral channels and 256 spatial samples. It includes: 1) the removal of artifacts associated to calibration residuals and/or incomplete flat field correction; 2) the reduction of the non-poissonian noise introduced by the readout electronics of the instrument; 3) a newer version of the radiometric calibration using stellar sources. Furthermore, we have modeled the thermal emission to remove the nucleus contribution at wavelengths in excess of 3.0 micron and we have also modeled and removed, by means of the Hapke model, the contribution of water ice absorption to isolate the organic features within the spectral region 2.9 - 3.5 micron. These spectral features have been compared with laboratory measurements and observations of diffuse interstellar medium to provide indications on the relative contribution of the Aromatic and Aliphatic components.
Published: 2018

49. Retrieving the distribution of comet 67P/Churyumov-Gerasimenko surface temperatures for individual Rosetta/VIRTIS-M spectra (pixel) by linear spectral unmixing - Method and first results

Author: Combe, J.-P., McCord, Thomas B., Capaccioni, F., Filacchione, G., Tosi, F., Ciarniello, M., Raponi, A., Kappel, David, and Rousseau, Batiste
Subjects: Asteroiden und Kometen, Rosetta, Comet 67P, Astrophysics::Earth and Planetary Astrophysics, VIRTIS, Surface temperatures
Abstract: Knowledge of surface temperature and its variations as function of illumination conditions is key for understanding the thermodynamical properties, the chemical properties and the physical structure of the regolith (porosity, roughness) of planets and small bodies in the solar system. The surface temperature can be retrieved from near-infrared spectra at wavelengths where thermal emission becomes non-negligible with respect to the reflected components. At 5 micron, the longest wavelength measured by VIRTIS-M on the Rosetta mission which observed comet 67P/Churyumov-Gerasimenko (67P/C-G), the minimum brightness temperature that can be measured is ~150K (instrumental noise equivalent temperature). The usual technique is to fit a Planck function to each spectrum, providing one temperature per pixel. However, the calculation of a distribution of temperatures per pixel is justified by the fact that the local topography changes at all scales resulting in variable illumination conditions (variable incidence angle and shadow casting) within the area covered by each pixel. This causes a distribution of temperatures which turns out in a distribution of thermal emission contributions. Furthermore, the combination of different thermal emission contributions (the linear combination of several Planck curves) is not a Planck function. Consequently, fitting one Planck function to a spectrum results in retrieving a value for the brightness temperature that is not representative of thermophysical properties of the regolith, because it is not the average of all temperatures in the area covered by that pixel.
Published: 2018

50. Studying surface morphologies of comet 67P/C-G using discrete element simulations

Author: Kappel, David, Otto, Katharina A., Oklay, Nilda, Michalik, Tanja, Haack, David, Kührt, Ekkehard, Tirsch, Daniela, Mottola, Stefano, and Groussin, Olivier
Subjects: Asteroiden und Kometen, Planetengeologie, Morphology, Discrete Element Modeling, Leitungsbereich PF, Comet 67P
Abstract: We use the discrete element method (DEM) to numerically simulate the surface layer regolith dynamics of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) in order to infer mechanical properties of the surface material.
Published: 2018

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