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1. VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis

Author: J. Krajewski, P. Aurard, Philippe Lamy, Vishnu Reddy, Laurent Jorda, D. Molina, Josef Hanus, Josef Ďurech, P. Michel, F. Vachier, Nicolas Rambaux, J. Oey, Grzegorz Dudziński, P. Bartczak, A. Leroy, Michael Marsset, L. Dalmon, P. Beck, H. Le Coroller, Hiroko Hamanowa, Maëlle Neveu, Christophe Dumas, Hiromi Hamanowa, A. G. Sanchez, Zouhair Benkhaldoun, N. Payre, E. Podlewska-Gaca, Fabrice Cipriani, Raoul Behrend, Paolo Tanga, Aled Jones, Julie Castillo-Rogez, Miroslav Brož, P. Antonini, Tadeusz Michalowski, F. Livet, O. Labrevoir, J. M. Bosch, Emmanuel Jehin, Arthur Vigan, S. Fauvaud, A. Chapman, Marin Ferrais, Jérôme Berthier, Alexis Drouard, Mirel Birlan, J. Grice, R. Montaigut, J. His, L. Socha, Romain Fétick, Olivier Witasse, Pierre Vernazza, Thierry Fusco, Benoit Carry, F. Marchis, Doeon Kim, Toni Santana-Ros, Mikko Kaasalainen, Matti Viikinkoski, P. Sabin, M. Audejean, A. Marciniak, Myung-Jin Kim, Bin Yang, Agnieszka Kryszczyńska, François Colas, 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), Institute of Astronomy [Prague], Charles University [Prague] (CU), Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Tampere University of Technology [Tampere] (TUT), Search for Extraterrestrial Intelligence Institute (SETI), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute of Romanian Academy, Romanian Academy, Adam Mickiewicz University in Poznań (UAM), Institut de Recherche en Horticulture et Semences (IRHS), Université d'Angers (UA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Liège, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), California Institute of Technology (CALTECH), European Space Agency (ESA), TMT Observatory, The Open University [Milton Keynes] (OU), Department of Mathematics [Tampere], University of Maryland [College Park], University of Maryland System, 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), Hospices Civils de Lyon (HCL), Research on Healthcare Performance (RESHAPE - Inserm U1290 - UCBL1), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM), Universidad de Alicante, Universitat de Barcelona (UB), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Observatoire de Chinon, Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Observatoire de Haute-Provence (OHP), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Geneva Observatory, University of Geneva [Switzerland], Université Cadi Ayyad [Marrakech] (UCA), Héritages et Constructions dans le Texte et l'Image (HCTI), Institut Brestois des Sciences de l'Homme et de la Société (IBSHS), Université de Brest (UBO)-Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Université de Brest (UBO), Observatoire du Bois de Bardon, Association T60, Observatoire 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Laboratory for Space Research [Hong Kong] (LSR), The University of Hong Kong (HKU), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Korea Astronomy and Space Science Institute (KASI), Okayama University, Chungbuk National University, Laboratoire d'analyse et de recherche en économie et finance internationales (Larefi), Université de Bordeaux (UB), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Anunaki Observatory, Sanofi-Aventis R&D, SANOFI Recherche, Planetary Science Institute [Tucson] (PSI), Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Ministerio de Economía y Competitividad (España), Belgian Science Policy Office, National Science Foundation (US), Generalitat Valenciana, Université Côte d'Azur (UCA), Université d'Angers (UA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Agence Spatiale Européenne = European Space Agency (ESA), 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 Genève = University of Geneva (UNIGE), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois des Sciences de l'Homme et de la Société (IBSHS), Université de Brest (UBO), 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)-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, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Tampere University, and Computing Sciences
Subjects: asteroids, Rotation period, Surface (mathematics), Shell (structure), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], general [Minor planets, asteroids], Context (language use), Astrophysics, 01 natural sciences, 03 medical and health sciences, Física Aplicada, 0103 physical sciences, 111 Mathematics, observational [Methods], 010303 astronomy & astrophysics, 030304 developmental biology, Physics, Asteroids:general, 0303 health sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Minor planets, techniques: high angular resolution, Astronomy and Astrophysics, 113 Computer and information sciences, asteroids: general, Bimodality, high angular resolution [Techniques], Density distribution, 115 Astronomy and space science, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], minor planets, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [Asteroids], high angular resolution, Shape analysis (digital geometry)
Abstract: Vernazza, P., et al., Until recently, the 3D shape, and therefore density (when combining the volume estimate with available mass estimates), and surface topography of the vast majority of the largest (D ≥ 100 km) main-belt asteroids have remained poorly constrained. The improved capabilities of the SPHERE/ZIMPOL instrument have opened new doors into ground-based asteroid exploration. Aims. To constrain the formation and evolution of a representative sample of large asteroids, we conducted a high-angular-resolution imaging survey of 42 large main-belt asteroids with VLT/SPHERE/ZIMPOL. Our asteroid sample comprises 39 bodies with D ≥ 100 km and in particular most D ≥ 200 km main-belt asteroids (20/23). Furthermore, it nicely reflects the compositional diversity present in the main belt as the sampled bodies belong to the following taxonomic classes: A, B, C, Ch/Cgh, E/M/X, K, P/T, S, and V. Methods. The SPHERE/ZIMPOL images were first used to reconstruct the 3D shape of all targets with both the ADAM and MPCD reconstruction methods.We subsequently performed a detailed shape analysis and constrained the density of each target using available mass estimates including our own mass estimates in the case of multiple systems. Results. The analysis of the reconstructed shapes allowed us to identify two families of objects as a function of their diameters, namely spherical and elongated bodies. A difference in rotation period appears to be the main origin of this bimodality. In addition, all but one object (216 Kleopatra) are located along the Maclaurin sequence with large volatile-rich bodies being the closest to the latter. Our results further reveal that the primaries of most multiple systems possess a rotation period of shorter than 6 h and an elongated shape (c=a ≤ 0.65). Densities in our sample range from ∼1.3 g cm-3 (87 Sylvia) to ∼4.3 g cm-3 (22 Kalliope). Furthermore, the density distribution appears to be strongly bimodal with volatile-poor (P ≥ 2.7 g cm-3) and volatile-rich (P ≤ 2.2 g cm-3) bodies. Finally, our survey along with previous observations provides evidence in support of the possibility that some C-complex bodies could be intrinsically related to IDP-like P- and D-type asteroids, representing different layers of a same body (C: core; P/D: outer shell). We therefore propose that P/ D-types and some C-types may have the same origin in the primordial trans-Neptunian disk., We warmly thank the ESO staff at Paranal and in particular Henri Boffin for providing us precious support and advice throughout the entire observing programme. P.V., A.D., M.F., L.J. and B.C. were supported by CNRS/INSU/PNP. The work of T.S-R. was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). TRAPPIST project is funded by the Belgian Fund for Scientic Research (Fond National de la Recherche Scientique, FNRS) under the grant PDR T.0120.21. E.J. is a FNRS Senior Research Associate. F.M. is supported by the National Science Foundation under Grant No. 1743015.
Published: 2021
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2. An advanced multipole model for (216) Kleopatra triple system

Author: Laurent Jorda, Josef Hanus, François Colas, Alexis Drouard, J. Grice, Julie Castillo-Rogez, Patrick Michel, Philippe Lamy, Pierre Vernazza, Josef Ďurech, Miroslav Brož, Bin Yang, Matti Viikinkoski, Franck Marchis, Tadeusz Michalowski, Marin Ferrais, Fabrice Cipriani, Thierry Fusco, Nicolas Rambaux, Olivier Witasse, Przemyslaw Bartczak, Arthur Vigan, David Vokrouhlický, Emmanuel Jehin, E. Podlewska-Gaca, Toni Santana-Ros, Frédéric Vachier, M. Pajuelo, Paolo Tanga, S. Benseguane, Romain Fétick, Christophe Dumas, Grzegorz Dudziński, Mirel Birlan, Agnieszka Kryszczyńska, S. Fauvaud, Anna Marciniak, Benoit Carry, J. Berthier, Michael Marsset, Institute of Astronomy [Prague], Charles University [Prague] (CU), Search for Extraterrestrial Intelligence Institute (SETI), 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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Tampere University of Technology [Tampere] (TUT), Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, SETI Institute, Ondřejov Observatory of the Prague Astronomical Institute, Czech Academy of Sciences [Prague] (CAS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire du Bois de Bardon, Astronomical Institute of Romanian Academy, Romanian Academy, Thirty Meter Telescope Observatory, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), Universidad de Alicante, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Czech Science Foundation, Charles University (Czech Republic), National Science Foundation (US), National Aeronautics and Space Administration (US), Generalitat Valenciana, Ministerio de Ciencia, Innovación y Universidades (España), Fédération Wallonie-Bruxelles, and Belgian Science Policy Office
Subjects: 010504 meteorology & atmospheric sciences, fundamental parameters [Planets and satellites], Library science, FOS: Physical sciences, Astrophysics, 01 natural sciences, methods: numerical, Física Aplicada, 0103 physical sciences, Celestial mechanics, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], numerical [Methods], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Minor planets, Astronomy and Astrophysics, Astrometry, celestial mechanics, asteroids: individual: (216) Kleopatra, individual: (216) Kleopatra [Asteroids], Space and Planetary Science, individual: (216) Kleopatra [Minor planets, asteroids], minor planets, astrometry, TRAPPIST, Christian ministry, Earth and Planetary Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: [Aims] To interpret adaptive-optics observations of (216) Kleopatra, we need to describe an evolution of multiple moons orbiting an extremely irregular body and include their mutual interactions. Such orbits are generally non-Keplerian and orbital elements are not constants. [Methods] Consequently, we used a modified N-body integrator, which was significantly extended to include the multipole expansion of the gravitational field up to the order ℓ = 10. Its convergence was verified against the 'brute-force' algorithm. We computed the coefficients Cℓ m, Sℓ m for Kleopatra's shape, assuming a constant bulk density. For Solar System applications, it was also necessary to implement a variable distance and geometry of observations. Our χ2 metric then accounts for the absolute astrometry, the relative astrometry (second moon with respect to the first), angular velocities, and silhouettes, constraining the pole orientation. This allowed us to derive the orbital elements of Kleopatra's two moons. [Results] Using both archival astrometric data and new VLT/SPHERE observations (ESO LP 199.C-0074), we were able to identify the true periods of the moons, P1 = (1.822359 ± 0.004156) d, P2 = (2.745820 ± 0.004820) d. They orbit very close to the 3:2 mean-motion resonance, but their osculating eccentricities are too small compared to other perturbations (multipole, mutual), meaning that regular librations of the critical argument are not present. The resulting mass of Kleopatra, m1 = (1.49 ± 0.16) × 10-12 M· or 2.97 × 1018 kg, is significantly lower than previously thought. An implication explained in the accompanying paper is that (216) Kleopatra is a critically rotating body., Broz, M. et al., This work has been supported by the Czech Science Foundation through grant 21-11058S (M. Brož, D. Vokrouhlický), 20-08218S (J. Hanuš, J. Ďurech), and by the Charles University Research program No. UNCE/SCI/023. This material is partially based upon work supported by the National Science Foundation under Grant No. 1743015. P.V., A.D., M.F. and B.C. were supported by CNRS/INSU/PNP. M.M. was supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0849 issued through the Planetary Astronomy Program. The work of TSR was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F. TRAPPIST-North is a project funded by the University of Liège, and performed in collaboration with Cadi Ayyad University of Marrakesh. E. Jehin is a FNRS Senior Research Associate.
Published: 2021
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3. Influence of Extreme Ultraviolet Irradiance Variations on the Precipitating Ion Flux From MAVEN Observations

Author: Janet G. Luhmann, Yaxue Dong, Ludivine Leclercq, Shannon Curry, François Leblanc, Ronan Modolo, Dmitri Titov, Francis G. Eparvier, Antoine Martinez, Jasper Halekas, J. P. McFadden, Robert Lillis, Takuya Hara, Olivier Witasse, Bruce M. Jakosky, Jean-Yves Chaufray, HELIOS - 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Department of Materials Science and Engineering [Charlottesville] (MS), University of Virginia [Charlottesville], and European Space Agency (ESA)
Subjects: Materials science, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Extreme ultraviolet lithography, Irradiance, Atmosphere of Mars, Astrophysics, 010502 geochemistry & geophysics, 7. Clean energy, 01 natural sciences, Ion, Atmosphere, Solar wind, Geophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Sputtering, Extreme ultraviolet, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences
Abstract: International audience; We study the influence of the solar extreme ultraviolet (EUV) flux intensity on the precipitating ion fluxes as seen by the Solar Wind Ion Analyzer, an energy and angular ion spectrometer aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We defined three periods with significantly different EUV flux intensity (1.6 and 3.2 times the lowest EUV intensity) and compare the precipitating ion flux measured by MAVEN/Solar Wind Ion Analyzer during each period. At low energy [30–650] eV, we find that the median (average) precipitating ion flux during the medium and low EUV periods are, respectively, 1.7 (2.1) and 3 (3.5) times more intense than the flux during the high EUV period. At high energy [650–25,000] eV, a similar trend in the intensity of the precipitating ion flux is observed but with an increase by 50% (46%) and 70% (79%), respectively. A larger EUV flux does therefore not seem to favor heavy ion precipitation into Mars's atmosphere, contrary to modeling prediction and overall expectations.
Published: 2019
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4. Origin of the Extended Mars Radar Blackout of September 2017

Author: Hermann Opgenoorth, François Leblanc, Nicolas Floury, Andrea Cicchetti, Robert Lillis, Mark Lester, Roberto Orosei, Pierre-Louis Blelly, John M. C. Plane, Andrew Kopf, Philip Conroy, M. Cartacci, Beatriz Sánchez-Cano, Olivier Witasse, Raffaella Noschese, Stephen E. Milan, Radio and Space Plasma Physics Group [Leicester] (RSPP), University of Leicester, 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), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Istituto di Radioastronomia [Bologna] (IRA), Department of Physics [Umeå], Umeå University, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, HELIOS - 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), School of Chemistry [Leeds], University of Leeds, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], ITA, USA, GBR, FRA, 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), Agence Spatiale Européenne = European Space Agency (ESA), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), and 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)
Subjects: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, Meteorology, Solar energetic particles, MARSIS, Mars Exploration Program, Atmosphere of Mars, Space weather, Fusion, Plasma and Space Physics, 01 natural sciences, law.invention, Fusion, plasma och rymdfysik, Orbiter, Geophysics, 13. Climate action, Space and Planetary Science, law, Environmental science, Ionosphere, Radar, 0105 earth and related environmental sciences
Abstract: The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) onboard Mars Express, which operates between 0.1 and 5.5 MHz, suffered from a complete blackout for 10 days in September 2017 when observing on the nightside (a rare occurrence). Moreover, the Shallow Radar (SHARAD) onboard the Mars Reconnaissance Orbiter, which operates at 20 MHz, also suffered a blackout for three days when operating on both dayside and nightside. We propose that these blackouts are caused by solar energetic particles of few tens of keV and above associated with an extreme space weather event between 10 and 22 September 2017, as recorded by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Numerical simulations of energetic electron precipitation predict that a lower O-2(+) nighttime ionospheric layer of magnitude similar to 10(10) m(-3) peaking at similar to 90-km altitude is produced. Consequently, such a layer would absorb radar signals at high frequencies and explain the blackouts. The peak absorption level is found to be at 70-km altitude. Plain Language Summary Several instrument operations, as well as communication systems with rovers at the surface, depend on radio signals that propagate throughout the atmosphere of Mars. This is the case also for two radars that are currently working in Mars' orbit, sounding the ionosphere, surface, and subsurface of the planet. In mid-September 2017, a powerful solar storm hit Mars, producing a large amount of energetic particle precipitation over a 10-day period. We have found that high-energy electrons ionized the atmosphere of Mars, creating a dense layer of ions and electrons at similar to 90 km on the Martian nightside. This layer attenuated radar signals continuously for 10 days, stopping the radars to receive any signal from the planetary surface. In this work, we assess the properties of this layer in order to understand the implications of this kind of phenomenon for radar performance and communications.
Published: 2019
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5. Interaction of Space Weather Phenomena with Mars Plasma Environment During Solar Minimum 23/24

Author: Andrey Fedorov, Hans Nilsson, P. Kajdič, Beatriz Sánchez-Cano, G. C. Bernal, L. Neves-Ribeiro, Diana Rojas-Castillo, and Olivier Witasse
Subjects: Solar minimum, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Space weather, 01 natural sciences, Physics - Space Physics, Astrophysics::Solar and Stellar Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Plasma, Mars Exploration Program, Bow shocks in astrophysics, Physics - Plasma Physics, Space Physics (physics.space-ph), Plasma Physics (physics.plasm-ph), Solar wind, Geophysics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Orbit (dynamics), Dynamic pressure, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We study the interaction of three solar wind structures, two stream interaction regions and one interplanetary coronal mass ejection, with Mars' plasma environment during 20-27 November 2007. This period corresponds to the solar minimum between the solar cycles 23 and 24 which was characterized by very low values of the solar wind density and dynamic pressure and low IMF magnitude. During that time the Mars-Express orbit was in the terminator plane, while the Earth, Sun, and Mars were almost aligned, so we use the ACE and STEREO probes as solar wind monitors in order to identify and characterize the structures that later hit Mars. We find that the passage of these structures caused strong variations of in the bow shock location (between 2.2 and 3.0~R$_M$), compression of the magnetospheric cavity (up to 45~\%) and an increased transterminator flow below 2~R$_M$ (by a factor of $\leq$8). This study shows that during times of low solar activity, modest space weather phenomena may cause large variations of plasma flow at Mars., Comment: Published in Journal of Geophysical Research
Published: 2021
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6. Evidence for differentiation of the most primitive small bodies

Author: Pierre Vernazza, Tadeusz Michalowski, Bin Yang, Matti Viikinkoski, Brian Warner, Agnieszka Kryszczyńska, Alexis Drouard, Alexander Storrs, Franck Marchis, J. Grice, François Colas, Patrick Michel, Laurent Jorda, Romain Fétick, Przemyslaw Bartczak, Arthur Vigan, Josef Ďurech, Marc Neveu, Frédéric Vachier, Julie Castillo-Rogez, Emmanuel Jehin, Michael Marsset, Josef Hanus, Nicolas Rambaux, Josselin Desmars, Mikko Kaasalainen, Marin Ferrais, Jérôme Berthier, Olivier Witasse, Philippe Lamy, Zouhair Benkhaldoun, E. Podlewska-Gaca, Fabrice Cipriani, Grzegorz Dudziński, Thierry Fusco, Raoul Behrend, Christophe Dumas, Anna Marciniak, Mirel Birlan, M. Pajuelo, Paolo Tanga, Benoit Carry, T. Santana-Ros, Mark A. Wieczorek, Joseph Louis LAGRANGE (LAGRANGE), 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Maryland [College Park], University of Maryland System, NASA Goddard Space Flight Center (GSFC), Institute of Astronomy [Prague], Charles University [Prague], Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Department of Mathematics [Tampere], Tampere University of Technology [Tampere] (TUT), Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), Geneva Observatory, University of Geneva [Switzerland], Oukaimeden Observatory, University of Cadi Ayyad (UCA), Astronomical Institute of Romanian Academy, Romanian Academy, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Institut Polytechnique des Sciences Avancées (IPSA), Thirty Meter Telescope Observatory, The Open University [Milton Keynes] (OU), University of Tampere [Finland], HELIOS - 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), SETI Institute, Pontificia Universidad Católica del Perú (PUCP), Institute of Physics [Szczecin], University of Szczecin, Universidad de Alicante, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Towson University [Towson, MD, United States], Center for Solar System Studies (CS3), European Southern Observatory (ESO), Czech Science Foundation, Charles University (Czech Republic), Generalitat de Catalunya, Ministerio de Ciencia, Innovación y Universidades (España), National Science Foundation (US), Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Charles University [Prague] (CU), Université de Genève = University of Geneva (UNIGE), Université Cadi Ayyad [Marrakech] (UCA), Agence Spatiale Européenne = European Space Agency (ESA), 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), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), 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), Tampere University, and Computing Sciences
Subjects: asteroids, Solar System, 010504 meteorology & atmospheric sciences, individual: Sylvia [Asteroids], individual: Sylvia [Minor planets, asteroids], FOS: Physical sciences, general [Minor planets, asteroids], Astrophysics, 01 natural sciences, Kuiper belt, Jupiter, Interplanetary dust cloud, Neptune, Física Aplicada, 0103 physical sciences, 111 Mathematics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Nodal precession, Sylvia, Minor planets, Astronomy and Astrophysics, general [Kuiper belt], 113 Computer and information sciences, Asteroids: general, Meteorite, 115 Astronomy and space science, 13. Climate action, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], Carbonaceous chondrite, Minor plantes, Asteroids: individual: Sylvia, Kuiper belt: general, general [Asteroids], Astrophysics - Earth and Planetary Astrophysics
Abstract: Carri, B., et al., [Context] Dynamical models of Solar System evolution have suggested that the so-called P- and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune's orbit and may be genetically related to the Jupiter Trojans, comets, and small Kuiper belt objects (KBOs). Indeed, the spectral properties of P- and D-type asteroids resemble that of anhydrous cometary dust. Aims. We aim to gain insights into the above classes of bodies by characterizing the internal structure of a large P- and D-type asteroid. [Methods] We report high-angular-resolution imaging observations of the P-type asteroid (87) Sylvia with the Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. These images were used to reconstruct the 3D shape of Sylvia. Our images together with those obtained in the past with large ground-based telescopes were used to study the dynamics of its two satellites. We also modeled Sylvia's thermal evolution. [Results] The shape of Sylvia appears flattened and elongated (a/b 1.45; a/c 1.84). We derive a volume-equivalent diameter of 271 ± 5 km and a low density of 1378 ± 45 kg m-3. The two satellites orbit Sylvia on circular, equatorial orbits. The oblateness of Sylvia should imply a detectable nodal precession which contrasts with the fully-Keplerian dynamics of its two satellites. This reveals an inhomogeneous internal structure, suggesting that Sylvia is differentiated. [Conclusions] Sylvia's low density and differentiated interior can be explained by partial melting and mass redistribution through water percolation. The outer shell should be composed of material similar to interplanetary dust particles (IDPs) and the core should be similar to aqueously altered IDPs or carbonaceous chondrite meteorites such as the Tagish Lake meteorite. Numerical simulations of the thermal evolution of Sylvia show that for a body of such a size, partial melting was unavoidable due to the decay of long-lived radionuclides. In addition, we show that bodies as small as 130-150 km in diameter should have followed a similar thermal evolution, while smaller objects, such as comets and the KBO Arrokoth, must have remained pristine, which is in agreement with in situ observations of these bodies. NASA Lucy mission target (617) Patroclus (diameter ≈140 km) may, however, be differentiated., This work has been supported by the Czech Science Foundation through grants 20-08218S (J. Hanuš, J. Ďurech) and by the Charles University Research program No. UNCE/SCI/023. The work of TSR was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). This material is partially based upon work supported by the National Science Foundation under Grant No. 1743015.
Published: 2021
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7. Galactic cosmic ray modulation at Mars and beyond measured with EDACs on Mars Express and Rosetta

Author: Robert F. Wimmer-Schweingruber, Olivier Witasse, A. Johnstone, Michel Denis, Mark Lester, E. W. Knutsen, J. Godfrey, Beatriz Sánchez-Cano, 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), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), School of Physics and Astronomy [Leicester], University of Leicester, Institute of Experimental and Applied Physics [Kiel] (IEAP), Christian-Albrechts-Universität zu Kiel (CAU), European Space Operations Center (ESOC), and Christian-Albrechts University of Kiel
Subjects: 010504 meteorology & atmospheric sciences, Astronomical unit, Cosmic ray, Astrophysics, 01 natural sciences, 7. Clean energy, Space exploration, Heliophysics, cosmic rays, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Physics, Spacecraft, business.industry, heliosphere, Astronomy, Astronomy and Astrophysics, Mars Exploration Program, Solar cycle, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], space vehicles, business, interplanetary medium, Heliosphere
Abstract: Galactic Cosmic Rays (GCRs) are an intrinsic part of the heliospheric radiation environment, and an inevitable challenge to long-term space exploration. Here we show solar cycle induced GCR modulation at Mars in the period 2005-2020, along with GCR radial gradients, by utilising Mars Express and Rosetta engineering parameters compared to sunspot number time series. The engineering parameter used is called EDAC (Error Detection And Correction), a cumulative counter which is triggered by charged energetic particle causing memory errors in on-board computers. EDAC data provides a new way of gaining insight into the field of particle transport in the heliosphere, allowing us to circumvent the need for dedicated instrumentation as EDAC software is present on all spacecraft.This data set can be used to capture variations of GCRs in both space and time, yielding the same qualitative information as ground-based neutron monitors. Our analysis of the Mars Express EDAC parameter reveals a strong solar cycle GCR modulation, yielding an anticorrelation coefficient of -0.5 at a time lag of ~5.5 months. By combining Mars Express with Rosetta data, we calculate a 5.3% increase in EDAC count rates per astronomical unit, attributed to a radial gradient in GCR fluxes in accordance with established literature.The potential of engineering data for scientific purposes remains mostly unexplored. The results obtained from this work demonstrates, for the first time for heliophysics purposes, the usefulness of the EDAC engineering parameter, data mining and the utility of keeping missions operational for many years, providing complimentary data to nominal science instruments.
Published: 2021
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8. The lower dayside ionosphere of Mars from 14 years of MaRS radio science observations

Author: Martin Pätzold, Michael K. Bird, Gregorio J. Molina-Cuberos, Silvia Tellmann, Bernd Häusler, Kerstin Peter, Francisco Gonzalez-Galindo, Olivier Witasse, Helmholtz Association, National Aeronautics and Space Administration (US), German Research Foundation, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, and European Space Agency
Subjects: 010504 meteorology & atmospheric sciences, Mars, Astrophysics, 01 natural sciences, law.invention, Radio Science, Atmosphere, law, 0103 physical sciences, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Ionosphere, 010303 astronomy & astrophysics, Zenith, 0105 earth and related environmental sciences, Physics, Solar flare, Astronomy and Astrophysics, Mars Exploration Program, Mars Eexpress, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Energy source, Flare
Abstract: This is an open access article under the CC BY-NC-ND license., This work uses a subset of “quiet” MaRS ionospheric dayside observations (MaRSquiet, 2004–2017) and a 1-D photochemical model (IonA-2) to investigate the potential formation processes of the excess electron densities merged with the base of the main ionosphere (Mm). 42% of the investigated MaRS observations contain identified Mm, which occur in a large variety of shapes ranging from smoothly decreasing electron densities to peak structures below the base of M1. The Mm appear over the full range of accessible solar zenith angles (50° - 90°) and are found between approximately 70 and 110 km altitude. Their base is found on average deeper in the atmosphere than the base of the averaged undisturbed MaRS electron density profiles. This indicates a dependence of the Mm formation on energy sources that penetrate deep into the atmosphere. This is supported by a strong positive correlation with increasing solar activity when solar flares, coronal mass ejections, and enhanced short solar X-ray and Ly-α intensities are more common. No relationship is found between the Mm occurrence rate and the magnitude/inclination of the weak crustal crustal magnetic field in MaRSquiet. Investigations with the IonA-2 photochemical model for undisturbed and flare conditions show that the ionization of the local neutral atmosphere by solar X-ray radiation, The Mars Express Radio Science Experiment (MaRS) is funded by the German Space Agency (DLR) under the Grant 50QM1802. Support for Mars Express Radio Science at Stanford University is provided by NASA through a JPL Contract. Support for the Multimission Radio Science Support Team is provided by NASA/JPL. Portions of this research were performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with NASA. We thank everyone involved in the Mars Express project at ESTEC, ESOC, ESAC, JPL, and the ESTRACK and DSN ground stations for their continuous support. K. P. and M. P. acknowledge funding for this project by the Deutsche Forschungsgemeinschaft (DFG) under Grant PA 525/11-1, PA525/11-2 and PA 525/14-1. F.G.G. is funded by the Spanish Ministerio de Ciencia, Innovacion y Universidades, the Agencia Estatal de Investigacion and EC FEDER funds under project RTI2018-100920-J-I00, and acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709). Solar Irradiance Platform historical irradiances are provided courtesy of W. Kent Tobiska and Space Environment Technologies. These historical irradiances have been developed with partial funding from the NASA UARS, TIMED, and SOHO missions. We acknowledge support for work conducted on the development of the Mars Climate Database from the European Space Agency (under ESTEC Contract 11369/95/NL/JG(SC)) and from CNES. CNRS (LMD group), the IAA and the UK Particle Physics and Astronomy Research Council (AOPP, Oxford Group) also provided support during the development of the Martian General Circulation Models.
Published: 2021

9. Science Goals and Mission Objectives for the Future Exploration of Ice Giants Systems: A Horizon 2061 Perspective

Author: J. Schmidt, Olivier Mousis, Sébastien Charnoz, Ravit Helled, Krista M. Soderlund, Olivier Witasse, Pierre Vernazza, Elizabeth P. Turtle, Nicolas André, Jonathan I. Lunine, Alexis Bouquet, L. Lamy, Corentin Louis, Magali Deleuil, Kathleen L. Craft, Kathleen Mandt, Léa Griton, Ricardo Hueso, Thomas Ronnet, Michel Blanc, Diego Turrini, University of Zurich, Blanc, Michel, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), 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: Solar System, 010504 meteorology & atmospheric sciences, 530 Physics, Computer science, 7. Clean energy, 01 natural sciences, Space exploration, Astrobiology, law.invention, Jupiter, Orbiter, 1912 Space and Planetary Science, Planet, Neptune, law, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Uranus, Astronomy and Astrophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, 10231 Institute for Computational Science, 3103 Astronomy and Astrophysics, Ice giant
Abstract: The comparative study of planetary systems is a unique source of new scientific insight: following the six “key science questions” of the “Planetary Exploration, Horizon 2061” long-term foresight exercise, it can reveal to us the diversity of their objects (Question 1) and of their architectures (Question 2), help us better understand their origins (Question 3) and how they work (Question 4), find and characterize habitable worlds (Question 5), and ultimately, search for alien life (Question 6). But a huge “knowledge gap” exists which limits the applicability of this approach in the solar system itself: two of its secondary planetary systems, the ice giant systems of Uranus and Neptune, remain poorly explored. Starting from an analysis of our current limited knowledge of solar system ice giants and their systems in the light of these six key science questions, we show that a long-term plan for the space exploration of ice giants and their systems will greatly contribute to answer these questions. To do so, we identify the key measurements needed to address each of these questions, the destinations to choose (Uranus, Neptune, Triton or a subset of them), the combinations of space platform(s) and the types of flight sequences needed. We then examine the different launch windows available until 2061, using a Jupiter fly-by, to send a mission to Uranus or Neptune, and find that: (1) an optimized choice of platforms and flight sequences makes it possible to address a broad range of the key science questions with one mission at one of the planets. Combining an atmospheric entry probe with an orbiter tour starting on a high-inclination, low periapse orbit, followed by a sequence of lower inclination orbits (or the other way around) appears to be an optimal choice. (2) a combination of two missions to each of the ice giant systems, to be flown in parallel or in sequence, will address five out of the six key questions and establish the prerequisites to address the sixth one: searching for life at one of the most promising Ice Giant moons. (3) The 2032 Jupiter fly-by window, which offers a unique opportunity to implement this plan, should be considered in priority; if this window cannot be met, using the 2036 Jupiter fly-by window to send a mission to Uranus first, and then the 2045 window for a mission to Neptune, will allow one to achieve the same objectives; as a back-up option, one should consider an orbiter + probe mission to one of the planets and a close fly-by of the other planet to deliver a probe into its atmosphere, using the opportunity of a future mission on its way to Kuiper Belt Objects or the interstellar medium; (4) based on the examination of the habitability of the different moons by the first two missions, a third one can be properly designed to search for life at the most promising moon, likely Triton, or one of the active moons of Uranus. Thus, by 2061 the first two missions of this plan can be implemented and a third mission focusing on the search for life can be designed. Given that such a plan may be out of reach of a single national agency, international collaboration is the most promising way to implement it.
Published: 2020
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10. Volume uncertainty of (7) Iris shape models from disc-resolved images

Author: Laurent Jorda, P. Michel, Miroslav Brož, Michael Marsset, P. Bartczak, H. Le Coroller, Jérôme Berthier, Matti Viikinkoski, Paolo Tanga, Marin Ferrais, Benoit Carry, Arthur Vigan, Bin Yang, Pierre Vernazza, P. L. Lamy, Christophe Dumas, Tadeusz Michalowski, Toni Santana-Ros, Alexis Drouard, Romain Fétick, Grzegorz Dudziński, Julie Castillo-Rogez, M. Birlan, F. Vachier, S. Benseguane, Thierry Fusco, Agnieszka Kryszczyńska, E. Podlewska-Gaca, Fabrice Cipriani, Olivier Witasse, F. Marchis, Josef Hanus, Nicolas Rambaux, Emmanuel Jehin, A. Marciniak, François Colas, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Adam Mickiewicz University in Poznań (UAM), Astronomical Observatory [Poznan], Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Charles University [Prague] (CU), Institute of Astronomy [Prague], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), SETI Institute, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), University of Tampere [Finland], Astronomical Institute of Romanian Academy, Romanian Academy, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), TMT International Observatory, 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), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Señal [Alicante] (DFESTS), Universidad de Alicante, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), European Project: 871149,EPN2024-RI, Czech Science Foundation, European Commission, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
Subjects: asteroids, Surface (mathematics), Solar System, 010504 meteorology & atmospheric sciences, photometric -minor planets, Instrumentation, 01 natural sciences, Física Aplicada, 0103 physical sciences, medicine, Angular resolution, individual, Iris (anatomy), Adaptive optics, 010303 astronomy & astrophysics, individual: (7) Iris [Minor planets, asteroids], 0105 earth and related environmental sciences, Remote sensing, instrumentation, Physics, numerical [Methods], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], photometric [Techniques], Astronomy and Astrophysics, adaptive optics -methods, Light curve, adaptive optics [Instrumentation], numerical -techniques, medicine.anatomical_structure, Space and Planetary Science, Asteroid, Astrophysics::Earth and Planetary Astrophysics
Abstract: High angular resolution disc-resolved images of (7) Iris collected by VLT/SPHERE instrument are allowed for the detailed shape modelling of this large asteroid revealing its surface features. If (7) Iris did not suffer any events catastrophic enough to disrupt the body (which is very likely) by studying its topography, we might get insights into the early Solar system’s collisional history. When it comes to internal structure and composition, thoroughly assessing the volume and density uncertainties is necessary. In this work, we propose a method of uncertainty calculation of asteroid shape models based on light curve and adaptive optics (AO) images. We apply this method on four models of (7) Iris produced from independent Shaping Asteroids using Genetic Evolution and All-Data Asteroid Modelling inversion techniques and multiresolution photoclinometry by deformation. Obtained diameter uncertainties stem from both the observations from which the models were scaled and the models themselves. We show that despite the availability of high-resolution AO images, the volume and density of (7) Iris have substantial error bars that were underestimated in the previous studies., This work has been supported by the Czech Science Foundation through grant 20-08218S (JH, MB) and by the Charles University Research program No. UNCE/SCI/023. This work has been partially supported by Horizon 2020 grant no. 871149 ‘EPN-2024-RI’.
Published: 2020
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11. Binary asteroid (31) Euphrosyne: ice-rich and nearly spherical

Author: Emmanuel Jehin, Josef Hanus, Christophe Dumas, Franck Marchis, Frédéric Vachier, Nicolas Rambaux, Pierre Vernazza, Romain Fétick, Marin Ferrais, Zouhair Benkhaldoun, M. Pajuelo, Paolo Tanga, Bin Yang, A. Marciniak, Olivier Witasse, Matti Viikinkoski, E. Podlewska-Gaca, Fabrice Cipriani, Ondrej Chrenko, Philippe Lamy, Laurent Jorda, François Colas, J. Grice, Tadeusz Michalowski, Julie Castillo-Rogez, Josef Ďurech, Mikko Kaasalainen, Grzegorz Dudziński, Michael Marsset, Patrick Michel, Mirel Birlan, Przemyslaw Bartczak, Alexis Drouard, Toni Santana-Ros, Jérôme Berthier, Miroslav Brož, Arthur Vigan, P. Ševeček, Benoit Carry, Thierry Fusco, Agnieszka Kryszczyńska, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Institute of Astronomy [Prague], Charles University [Prague] (CU), 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'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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), University of Tampere [Finland], Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), Search for Extraterrestrial Intelligence Institute (SETI), Astronomical Institute of Romanian Academy, Romanian Academy, Oukaimeden Observatory, Université Cadi Ayyad [Marrakech] (UCA), Thirty Meter Telescope Observatory, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), DOTA, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), 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), Pontificia Universidad Católica del Perú (PUCP), Universidad de Alicante, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), 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), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), Czech Science Foundation, Charles University (Czech Republic), Ministry of Education, Youth and Sports (Czech Republic), Centre National de la Recherche Scientifique (France), National Aeronautics and Space Administration (US), Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles), and Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal
Subjects: individual: (31) Euphrosyne / minor planets [Asteroids], 010504 meteorology & atmospheric sciences, general [Minor planets, asteroids], FOS: Physical sciences, Astrophysics, Asteroids: individual: (31) Euphrosyne / minor planets, 01 natural sciences, Sphericity, law.invention, Techniques: high angular resolution, Impact crater, law, Física Aplicada, 0103 physical sciences, observational [Methods], Circular orbit, 010303 astronomy & astrophysics, individual: (31) Euphrosyne [Minor planets, asteroids], ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, high angular resolution [Techniques], Orbit, Asteroids: general, Methods: observational / minor planets, Space and Planetary Science, Asteroid, Satellite, observational / minor planets [Methods], Hydrostatic equilibrium, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [Asteroids], Astrophysics - Earth and Planetary Astrophysics, Shape analysis (digital geometry)
Abstract: Aims. Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event. Methods. The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. Results. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2 m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the Genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Conclusions. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne's diameter is 268 ± 6 km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne - S/2019 (31) 1 - that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665 ± 242 kg m-3, suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10) Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation., This work has been supported by the Czech Science Foundation through grant 18-09470S (J. Hanuš, O. Chrenko, P. Ševecˇek) and by the Charles University Research program No. UNCE/SCI/023. M.B. was supported by the Czech Science Foundation grant 18-04514J. Computational resources were supplied by the Ministry of Education, Youth and Sports of the Czech Republic under the projects CESNET (LM2015042) and IT4Innovations National Supercomputing Centre (LM2015070). P. Vernazza, A. Drouard, M. Ferrais and B. Carry were supported by CNRS/INSU/PNP. M.M. was supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0849 issued through the Planetary Astronomy Program. The work of TSR was carried out through grant APOSTD/2019/046 by Generalitat Valen-ciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F. TRAPPIST-North is a project funded by the Université de Liège, and performed in collaboration with Cadi Ayyad University of Marrakesh. E. Jehin is a FNRS Senior Research Associate.
Published: 2020
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12. In Situ Data and Effect Correlation During September 2017 Solar Particle Event

Author: Natalia Vlasova, Piers Jiggens, Ingmar Sandberg, Ilya Usoskin, Miikka Paassilta, Pentti Nieminen, Arttu Punkkinen, Alexander Mishev, Hannu Leppinen, Eamonn Daly, Ulrich Straube, Olivier Witasse, D. Heynderickx, Hugh Evans, T. P. O'Brien, Thomas Berger, Jaan Praks, Vladimir Kalegaev, Beatriz Sánchez-Cano, Donald M. Hassler, J. E. Mazur, Tsutomu Nagatsuma, Christian Poivey, C. Clavie, Rami Vainio, Petri Niemelä, Sylvie Benck, Stanislav Borisov, Daniel Müller, Mathias Cyamukungu, Sigiava Aminalragia-Giamini, European Space Research and Technology Centre, European Space Agency - ESA, Aerospace Corporation, University of Oulu, Lomonosov Moscow State University, Université catholique de Louvain, DH Consultancy BVBA, Space Applications and Research Consultancy, German Aerospace Center, University of Turku, University of Leicester, Southwest Research Institute, Department of Electronics and Nanoengineering, Space Systems Finland Oy, Japan National Institute of Information and Communications Technology, Aalto-yliopisto, and Aalto University
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, 01 natural sciences, Strahlenbiologie, SEEs, 0103 physical sciences, Coronal mass ejection, Particle radiation, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Radiation, ta115, Neutron monitor, Solar energetic particles, dose, Computational physics, radiation, SEP, GLE, Physics::Space Physics, Solar particle event, SPE, Interplanetary spaceflight, Event (particle physics), Heliosphere
Abstract: Solar energetic particles are one of the main sources of particle radiation seen in space. In the first part of September 2017 the most active solar period of cycle 24 produced four large X-class flares and a series of (interplanetary) coronal mass ejections, which gave rise to radiation storms seen over all energies and at the ground by neutron monitors. This paper presents comprehensive cross comparisons of in situ radiation detector data from near-Earth satellites to give an appraisal on the state of present data processing for monitors of such particles. Many of these data sets have been the target of previous cross calibrations, and this event with a hard spectrum provides the opportunity to validate these results. As a result of the excellent agreement found between these data sets and the use of neutron monitor data, this paper also presents an analytical expression for fluence spectrum for the event. Derived ionizing dose values have been computed to show that although there is a significant high-energy component, the event was not particularly concerning as regards dose effects in spacecraft electronics. Several sets of spacecraft data illustrating single event effects are presented showing a more significant impact in this regard. Such a hard event can penetrate thick shielding; human dose quantities measured inside the International Space Station and derived through modeling for aircraft altitudes are also presented. Lastly, simulation results of coronal mass ejection propagation through the heliosphere are presented along with data from Mars-orbiting spacecraft in addition to data from the Mars surface.
Published: 2019
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13. Interplanetary coronal mass ejection observed at STEREO-A, Mars, comet 67P/Churyumov-Gerasimenko, Saturn, and New Horizons en route to Pluto: Comparison of its Forbush decreases at 1.4, 3.1, and 9.9 AU

Author: I. Zouganelis, Lucile Turc, James L. Burch, J. Zender, Robert F. Wimmer-Schweingruber, H. Evans, Dusan Odstrcil, Donald M. Hassler, Stas Barabash, G. Provan, M. Holmstrom, Holger Nilsson, Mark Lester, P. Niemenen, Stan W. H. Cowley, Jared Espley, Charlotte Goetz, Matthew K. James, Ingo Richter, Hermann Opgenoorth, B. E. S. Hall, Elias Roussos, John D. Richardson, Jean-Pierre Lebreton, Christoph Koenders, Olivier Witasse, Vincent Génot, Ian G. Richardson, David Andrews, Norbert Krupp, Kathleen Mandt, Arik Posner, H. A. Elliott, E. Kuulkers, Jingnan Guo, Raymond Goldstein, Nicolas Altobelli, Robin Ramstad, Henning Lohf, J. J. Plaut, Stephen E. Milan, Beatriz Sánchez-Cano, Alexis P. Rouillard, Matthew Taylor, Primoz Kajdic, Michele K. Dougherty, Karl-Heinz Glassmeier, Niklas J. T. Edberg, D. Intzekara, M. L. Mays, and Etienne Behar
Subjects: Physics, Solar System, 010504 meteorology & atmospheric sciences, Comet, Astronomy, Mars Exploration Program, Space weather, 01 natural sciences, Pluto, Solar wind, Geophysics, 13. Climate action, Space and Planetary Science, Saturn, 0103 physical sciences, Forbush decrease, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We discuss observations of the journey throughout the Solar System of a large interplanetary coronal mass ejection (ICME) that was ejected at the Sun on 14 October 2014. The ICME hit Mars on 17 October, as observed by the Mars Express, MAVEN, Mars Odyssey and MSL missions, 44 hours before the encounter of the planet with the Siding-Spring comet, for which the space weather context is provided. It reached comet 67P/Churyumov-Gerasimenko, which was perfectly aligned with the Sun and Mars at 3.1 AU, as observed by Rosetta on 22 October. The ICME was also detected by STEREO-A on 16 October at 1 AU, and by Cassini in the solar wind around Saturn on the 12 November at 9.9 AU. Fortuitously, the New Horizons spacecraft was also aligned with the direction of the ICME at 31.6 AU. We investigate whether this ICME has a non-ambiguous signature at New Horizons. A potential detection of this ICME by Voyager-2 at 110-111 AU is also discussed. The multi-spacecraft observations allow the derivation of certain properties of the ICME, such as its large angular extension of at least 116°, its speed as a function of distance, and its magnetic field structure at four locations from 1 to 10 AU. Observations of the speed data allow two different solar wind propagation models to be validated. Finally, we compare the Forbush decreases (transient decreases followed by gradual recoveries in the galactic cosmic ray intensity) due to the passage of this ICME at Mars, comet 67P and Saturn.
Published: 2017
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14. A review of the in situ probe designs from recent ice giant mission concept studies

Author: Diego Turrini, David J. Atkinson, Olivier Witasse, Athena Coustenis, Amy Simon, Chris S. Arridge, Francesca Ferri, Kim Reh, Adam Masters, Mark Hofstadter, Leigh N. Fletcher, Olivier Mousis, The Royal Society, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, business.industry, Uranus, Astronomy and Astrophysics, Astronomy & Astrophysics, 01 natural sciences, 7. Clean energy, Planetary science, Space and Planetary Science, Neptune, Atmospheric entry, [SDU]Sciences of the Universe [physics], Space Shuttle thermal protection system, 0103 physical sciences, 0201 Astronomical and Space Sciences, Aeroshell, Environmental science, Aerospace engineering, business, Engineering design process, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Ice giant, 0105 earth and related environmental sciences
Abstract: International audience; For the Ice Giants, atmospheric entry probes provide critical measurements not attainable via remote observations. Including the 2013-2022 NASA Planetary Decadal Survey , there have been at least five comprehensive atmospheric probe engineering design studies performed in recent years by NASA and ESA. International science definition teams have assessed the science requirements, and each recommended similar measurements and payloads to meet science goals with current instrument technology. The probe system concept has matured and converged on general design parameters that indicate the probe would include a 1-meter class aeroshell and have a mass around 350 to 400-kg. Probe battery sizes vary, depending on the duration of a post-release coast phase, and assumptions about heaters and instrument power needs. The various mission concepts demonstrate the need for advanced power and thermal protection system development. 17 Page 2 of 13 A.A. Simon et al. show an Ice Giant mission with an in situ probe is feasible and would be welcomed by the international science community.
Published: 2020
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15. The violent collisional history of aqueously evolved (2) Pallas

Author: Alexis Drouard, Franck Marchis, Romain Fétick, Arthur Vigan, Miroslav Brož, Julie Castillo-Rogez, Herve Le Coroller, Christophe Dumas, Josef Hanus, Toni Santana-Ros, Paolo Tanga, Patrick Michel, Matti Viikinkoski, Mirel Birlan, E. Podlewska-Gaca, Fabrice Cipriani, Bin Yang, Nicolas Rambaux, Mikko Kaasalainen, Thierry Fusco, Grzegorz Dudziński, Tadeusz Michalowski, Benoit Carry, Agnieszka Kryszczyńska, Przemyslaw Bartczak, P. Ševeček, Jérôme Berthier, Laurent Jorda, Josef Ďurech, Michael Marsset, François Colas, Derek C. Richardson, Marin Ferrais, A. Marciniak, Frédéric Vachier, Erik Asphaug, Pierre Vernazza, Emmanuel Jehin, Olivier Witasse, Philippe Lamy, European Commission, National Aeronautics and Space Administration (US), Generalitat Valenciana, Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Astronomical Institute of Charles University, Charles University [Prague] (CU), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Mathematics [Tampere], Tampere University of Technology [Tampere] (TUT), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Search for Extraterrestrial Intelligence Institute (SETI), Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Faculty of Mathematics and Physics [Praha/Prague], Université de Liège, Les Afriques dans le monde (LAM), Sciences Po Bordeaux - Institut d'études politiques de Bordeaux (IEP Bordeaux)-Institut de Recherche pour le Développement (IRD)-Institut d'Études Politiques [IEP] - Bordeaux-Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Amgen (Europe) GmbH, De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Agence Spatiale Européenne = European Space Agency (ESA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Sciences Po Bordeaux - Institut d'études politiques de Bordeaux (IEP Bordeaux)-Institut de Recherche pour le Développement (IRD)-Institut d'Études Politiques [IEP] - Bordeaux-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS), and Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal
Subjects: Very Large Telescope, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Asteroid (2) Pallas, Violent collisional history, Astronomy and Astrophysics, Orbital eccentricity, Astrophysics, Aqueous alteration, Albedo, 01 natural sciences, Orbital inclination, Bright spot, Impact crater, 13. Climate action, Chondrite, Asteroid, Física Aplicada, 0103 physical sciences, 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: et al., Asteroid (2) Pallas is the largest main-belt object not yet visited by a spacecraft, making its surface geology largely unknown and limiting our understanding of its origin and collisional evolution. Previous ground-based observational campaigns returned different estimates of its bulk density that are inconsistent with one another, one measurement1 being compatible within error bars with the icy Ceres (2.16 ± 0.01 g cm−3)2 and the other3 compatible within error bars with the rocky Vesta (3.46 ± 0.03 g cm−3)4. Here we report high-angular-resolution observations of Pallas performed with the extreme adaptive optics-fed SPHERE imager5 on the Very Large Telescope. Pallas records a violent collisional history, with numerous craters larger than 30 km in diameter populating its surface and two large impact basins that could be related to a family-forming impact. Monte Carlo simulations of the collisional evolution of the main belt correlate this cratering record to the high average impact velocity of ~11.5 km s−1 on Pallas—compared with an average of ~5.8 km s−1 for the asteroid belt—induced by Pallas’s high orbital inclination (i = 34.8°) and orbital eccentricity (e = 0.23). Compositionally, Pallas’s derived bulk density of 2.89 ± 0.08 g cm−3 (1σ uncertainty) is fully compatible with a CM chondrite-like body, as suggested by its spectral reflectance in the 3 μm wavelength region6. A bright spot observed on its surface may indicate an enrichment in salts during an early phase of aqueous alteration, compatible with Pallas’s relatively high albedo of 12–17% (refs. 7,8), although alternative origins are conceivable., Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 199.C-0074 (principal investigator: P.V.). This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with NASA. M.M. was supported by the National Aeronautics and Space Administration under grant number 80NSSC18K0849 issued through the Planetary Astronomy Program. This work was supported by the French Direction Générale de l’Armement (DGA) and Aix-Marseille Université (AMU). P.V., A.D. and B.C. were supported by CNRS/INSU/PNP. J.H., J.D. and P.S. were supported by the grant 18-09470S of the Czech Science Foundation and by the Charles University Research Programme number UNCE/SCI/023. M.Brož was supported by the grant 18-04514J of the Czech Science Foundation. E.J. is a F.R.S.-FNRS Senior Research Associate. The work of T.S.-R. was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement number 730890.
Published: 2020
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16. A new method for determining the total electron content in Mars' ionosphere based on Mars Express MARSIS data

Author: Nicolas Floury, Roberto Orosei, Olivier Witasse, Wlodek Kofman, M. Cartacci, Beatriz Sánchez-Cano, Philip Conroy, G. Quinsac, ITA, GBR, FRA, NLD, and POL
Subjects: 010504 meteorology & atmospheric sciences, Total electron content, TEC, Astronomy and Astrophysics, MARSIS, Mars Exploration Program, 01 natural sciences, Ionospheric sounding, law.invention, Physics::Geophysics, Space and Planetary Science, law, Mars Orbiter Laser Altimeter, 0103 physical sciences, Physics::Space Physics, Radar, Ionosphere, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract: We present a new method for determining the total electron content (TEC) in the Martian ionosphere based on the time delay of received radar pulses of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board the Mars Express spacecraft. Previous studies of the same dataset have produced differing results for the day-side ionosphere, so it is useful to have an alternative way to compute the TEC in this region. This method iterates a model ionosphere in order to simultaneously match the ionospheric delays of the signals received by the radar’s two channels by finding the model which minimizes the root mean square error (RMSE) between the measured and simulated delays. Topographical information is obtained from data from the Mars Orbiter Laser Altimeter (MOLA) instrument. The model parameters are held constant for a given orbit, and a very good agreement between the simulated and measured delays is obtained. The TEC can then be inverted from the ionospheric model. Matching the delays of both channels simultaneously applies an additional constraint to the model which has not been made in previous studies. The model is additionally validated by matching the simulated pulses with the raw range-compressed measurements for one orbit. Finally, typical model parameters are compared to those obtained by previous studies, which are also simulated. The method is applied to orbits during moderate solar activity, and results show very good agreement with previous studies.
Published: 2020

17. Asteroid (16) Psyche’s primordial shape: A possible Jacobi ellipsoid

Author: P. Bartczak, A. Marciniak, E. Podlewska-Gaca, Bin Yang, Fabrice Cipriani, Miroslav Brož, Arthur Vigan, Tadeusz Michalowski, Julie Castillo-Rogez, F. Vachier, Patrick Michel, Benoit Carry, Olivier Witasse, François Colas, Pierre Vernazza, F. Marchis, Emmanuel Jehin, P. Lamy, Josef Hanus, Matti Viikinkoski, Nicolas Rambaux, Romain Fétick, Alexis Drouard, Toni Santana-Ros, H. Le Coroller, M. Birlan, Mikko Kaasalainen, Agnieszka Kryszczyńska, Laurent Jorda, Josef Ďurech, Michael Marsset, Grzegorz Dudziński, Paolo Tanga, Marin Ferrais, Thierry Fusco, Christophe Dumas, Jérôme Berthier, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, 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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute of Charles University, Charles University [Prague] (CU), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Tampere University of Technology [Tampere] (TUT), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Adam Mickiewicz University in Poznań (UAM), European Southern Observatory (ESO), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Astronomical Observatory [Poznan], Laboratoire associé de Reconnaissance cellulaire et amélioration des plantes, Institut National de la Recherche Agronomique (INRA), Department of Mathematics [Tampere], Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Northeastern University [Shenyang], European Southern Observatory, Centre National de la Recherche Scientifique (France), Czech Science Foundation, Charles University (Czech Republic), Generalitat Valenciana, European Commission, Ministerio de Economía y Competitividad (España), Tampere University, Computing Sciences, Research group: Inverse Problems, European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), 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, and 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)
Subjects: Rotation period, Solar System, asteroids: individual: (16) Psyche, 010504 meteorology & atmospheric sciences, lAsteroids: individual: (16) Psyche, individual: (16) Psyche [Asteroids], Context (language use), Astrophysics, individual: (16) Psyche [lAsteroids], 01 natural sciences, law.invention, law, Física Aplicada, 0103 physical sciences, observational [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, techniques: high angular resolution, Minor planets, Astronomy and Astrophysics, Ellipsoid, asteroids: general, Psyche, high angular resolution [Techniques], 13. Climate action, Space and Planetary Science, Asteroid, 115 Astronomy and space science, minor planets, Hydrostatic equilibrium, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [Asteroids], Shape analysis (digital geometry)
Abstract: Context. Asteroid (16) Psyche is the largest M-type asteroid in the main belt and the target of the NASA Psyche mission. It is also the only asteroid of this size (D> 200 km) known to be metal rich. Although various hypotheses have been proposed to explain the rather unique physical properties of this asteroid, a perfect understanding of its formation and bulk composition is still missing. Aims. We aim to refine the shape and bulk density of (16) Psyche and to perform a thorough analysis of its shape to better constrain possible formation scenarios and the structure of its interior. Methods. We obtained disk-resolved VLT/SPHERE/ZIMPOL images acquired within our ESO large program (ID 199.C-0074), which complement similar data obtained in 2018. Both data sets offer a complete coverage of Psyche's surface. These images were used to reconstruct the three-dimensional (3D) shape of Psyche with two independent shape modeling algorithms (MPCD and ADAM). A shape analysis was subsequently performed, including a comparison with equilibrium figures and the identification of mass deficit regions. Results. Our 3D shape along with existing mass estimates imply a density of 4.20 ± 0.60 g cm-3, which is so far the highest for a solar system object following the four telluric planets. Furthermore, the shape of Psyche presents small deviations from an ellipsoid, that is, prominently three large depressions along its equator. The flatness and density of Psyche are compatible with a formation at hydrostatic equilibrium as a Jacobi ellipsoid with a shorter rotation period of ∼3h. Later impacts may have slowed down Psyche's rotation, which is currently ∼4.2 h, while also creating the imaged depressions. Conclusions. Our results open the possibility that Psyche acquired its primordial shape either after a giant impact while its interior was already frozen or while its interior was still molten owing to the decay of the short-lived radionuclide 26Al., Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 199.C-0074 (principal investigator: P. Vernazza). P. Vernazza, A. Drouard, M. Ferrais and B. Carry were supported by CNRS/INSU/PNP. J.H. and J.D. were supported by grant 18-09470S of the Czech Science Foundation and by the Charles University Research Programme no. UNCE/SCI/023. E.J. is F.R.S.-FNRS Senior Research Associate. The work of TSR was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE).
Published: 2020
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18. Mars' Ionospheric Interaction With Comet C/2013 A1 Siding Spring's Coma at Their Closest Approach as Seen by Mars Express

Author: Alejandro Cardesín-Moinelo, David Andrews, Olivier Witasse, Mark Lester, Jared Espley, Andrew Kopf, Hermann Opgenoorth, Stanley W. H. Cowley, David Morgan, François Leblanc, Beatriz Sánchez – Cano, Pierre-Louis Blelly, Radio and Space Plasma Physics Group [Leicester] (RSPP), University of Leicester, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Department of Physics [Umeå], Umeå University, Swedish Institute of Space Physics [Uppsala] (IRF), 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), HELIOS - 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), NASA Goddard Space Flight Center (GSFC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), 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), and 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)
Subjects: Martian, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Electron density, 010504 meteorology & atmospheric sciences, Comet, Astronomy, MARSIS, Mars Exploration Program, 01 natural sciences, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Depth sounding, Geophysics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Coronal mass ejection, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Geology, 0105 earth and related environmental sciences
Abstract: International audience; On 19 October 2014, Mars experienced a close encounter with Comet C/2013 A1 Siding Spring. Using data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board Mars Express (MEX), we assess the interaction of the Martian ionosphere with the comet's coma and possibly magnetic tail during the orbit of their closest approach. The topside ionospheric electron density profile is evaluated from the altitude of the peak density of the ionosphere up to the Mars Express altitude. We find complex and rapid variability in the ionospheric profile along the MEX orbit, not seen even after the impact of a large coronal mass ejection. Before closest approach, large electron density reductions predominate, which could be caused either by comet water‐damping, or comet magnetic field interactions. After closest approach, a substantial electron density rise predominates. Moreover, several extra topside layers are visible along the whole orbit at different altitudes, which could be related to different processes as we discuss.
Published: 2020
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19. Participation of women scientists in ESA solar system missions: a historical trend

Author: Olivier Witasse, Miriam Rengel, Arianna Piccialli, Matthew Taylor, Pierre Drossart, Ann Carine Vandaele, Anny-Chantal Levasseur-Regourd, Julie A. Rathbun, Francesca Altieri, Anni Määttänen, Alessandra Rotundi, Anna Milillo, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Planetary Science Institute [Tucson] (PSI), 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), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Research and Scientific Support Department, ESTEC (RSSD), European Space Agency (ESA)-European Space Agency (ESA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: lcsh:Dynamic and structural geology, 010504 meteorology & atmospheric sciences, Inequality, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, media_common.quotation_subject, lcsh:QE1-996.5, General Medicine, Public relations, 01 natural sciences, Proxy (climate), lcsh:Geology, [SHS.HISPHILSO]Humanities and Social Sciences/History, Philosophy and Sociology of Sciences, lcsh:QE500-639.5, 5. Gender equality, Political science, 0103 physical sciences, Member state, lcsh:Q, lcsh:Science, business, [SHS.GENRE]Humanities and Social Sciences/Gender studies, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common
Abstract: We analyzed the participation of women scientists in 10 ESA (European Space Agency) Solar System missions over a period of 38 years. Being part of a spacecraft mission science team can be considered a proxy to measure the “success” in the field. Participation of women in PI (Principal Investigators) teams varied between 4 % and 25 %, with several missions with no women as PI. The percentage of female scientists as Co-I (Co-Investigators) is always less than 16 %. This number is lower than the percentage of women in the International Astronomical Union from all ESA's Member State (24 %), which can give us an indication of the percentage of women in the field. We encountered many difficulties to gather the data for this study. The list of team members were not always easily accessible. An additional difficulty was to determine the percentage of female scientists in planetary science in Europe. We would like to encourage the planetary community as a whole, as well as international organizations, universities and societies to continuously gather statistics over many years. Detailed statistics are only the first step to closely monitor the development of achievement gaps and initiate measures to tackle potential causes of inequity, leading to gender inequalities in STEM careers.
Published: 2020
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20. Influence of the solar wind dynamic pressure on the ion precipitation: MAVEN observations and simulation results

Author: Ronan Modolo, Janet G. Luhmann, Bruce M. Jakosky, Antoine Martinez, Yaxue Dong, Francis G. Eparvier, Jasper Halekas, Takuya Hara, J. P. McFadden, Olivier Witasse, Shannon Curry, Robert Lillis, François Leblanc, Norberto Romanelli, Jean-Yves Chaufray, Ludivine Leclercq, 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), HELIOS - 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), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), GSFC Solar System Exploration Division, NASA Goddard Space Flight Center (GSFC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], University of Virginia [Charlottesville], and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU)
Subjects: Materials science, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Energy flux, Flux, Magnetosphere, 01 natural sciences, 7. Clean energy, Ion, Computational physics, Atmosphere, Solar wind, Geophysics, 13. Climate action, Space and Planetary Science, Sputtering, [SDU]Sciences of the Universe [physics], Dynamic pressure, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience; We discuss the influence of the solar wind dynamic pressure on the ion precipitation using observations performed by MAVEN from the 04 June 2014 to the 20 July 2017. The increase of the dynamic pressure from 0.63 to 1.44nPa is clearly associated with an increase of the same order of magnitude of the precipitating oxygen ion energy flux measured by MAVEN/STATIC from 9.9 to 20.6 × 106eV. cm−2. sr−1. s−1at low energy (from 30 to 650 eV). In the same way, from 650 eV to 25000 eV, MAVEN/SWIA (all species) observed an increase from 22.4 to 42.8 × 107eV. cm−2. sr−1. s−1 of the precipitating ion energy flux.Performing two simulations using the average solar wind conditions for both solar dynamic pressure regimes observed by MAVEN as input of the LatHyS model (LATMOS Hybrid Simulation), we reproduce some of the key characteristics of the observed oxygen ion precipitation. We characterize the oxygen ions simulated by LatHyS by their energy and time of impact, their time of injection in the simulation and initial position and the mechanism by which these ions were created. The model suggests that the main cause of the increase of the heavy ion precipitation during an increase of the solar dynamic pressure is the increase of the ion production by charge exchange, proportional to the increase of the solar wind flux, which becomes the main contribution to the ion precipitation at high energy.
Published: 2020
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21. A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea

Author: J. Grice, Mikko Kaasalainen, F. Colas, A. Chapman, Tadeusz Michalowski, Arthur Vigan, Josef Hanus, Julie Castillo-Rogez, Róbert Szakáts, Marin Ferrais, Przemyslaw Bartczak, Benoit Carry, Miroslav Brož, Laurent Jorda, Nicolas Rambaux, Matti Viikinkoski, Grzegorz Dudziński, P. Michel, Agnieszka Kryszczyńska, Rene Duffard, Michaël Gillon, Michael Marsset, Jérôme Berthier, J. Durech, Bin Yang, Mirel Birlan, Christophe Dumas, R. Hirsch, Francesca E. DeMeo, F. Vachier, P. Lamy, Toni Santana-Ros, Thierry Fusco, Zouhair Benkhaldoun, E. Podlewska-Gaca, Fabrice Cipriani, P. Ševeček, H. Le Coroller, Olivier Witasse, A. Marciniak, F. Marchis, Emmanuel Jehin, J. L. Maestre, Alexis Drouard, Romain Fétick, Pierre Vernazza, Paolo Tanga, 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), Astronomical Institute of Charles University, Charles University [Prague] (CU), Tampere University of Technology [Tampere] (TUT), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Adam Mickiewicz University in Poznań (UAM), Institut d'Astrophysique et de Géophysique [Liège], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Centre de Biochimie Structurale [Montpellier] (CBS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Astronomical Observatory [Poznan], 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), Université Pierre et Marie Curie - Paris 6 (UPMC), LPHEA - Departement de Physique (LPHEA), Département de physique, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Agence Spatiale Européenne = European Space Agency (ESA), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (France), Czech Science Foundation, Charles University (Czech Republic), European Commission, Université Cadi Ayyad, and Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles)
Subjects: Rotation period, Solar System, 010504 meteorology & atmospheric sciences, Dwarf planet, VLT/SPHERE instrument, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Sphericity, Impact crater, Física Aplicada, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Asteroide, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Basin-free, Astronomy, Astronomy and Astrophysics, Radius, Asteroid family, High-angular-resolution imaging observation, Asteroids, Asteroid, [SDU]Sciences of the Universe [physics], Hygiea, Astrophysics::Earth and Planetary Astrophysics, Spherical shape, Giant impact
Abstract: (10) Hygiea is the fourth largest main belt asteroid and the only known asteroid whose surface composition appears similar to that of the dwarf planet (1) Ceres1,2, suggesting a similar origin for these two objects. Hygiea suffered a giant impact more than 2 Gyr ago3 that is at the origin of one of the largest asteroid families. However, Hygeia has never been observed with sufficiently high resolution to resolve the details of its surface or to constrain its size and shape. Here, we report high-angular-resolution imaging observations of Hygiea with the VLT/SPHERE instrument (~20 mas at 600 nm) that reveal a basin-free nearly spherical shape with a volume-equivalent radius of 217 ± 7 km, implying a density of 1,944 ± 250 kg m− 3 to 1σ. In addition, we have determined a new rotation period for Hygiea of ~13.8 h, which is half the currently accepted value. Numerical simulations of the family-forming event show that Hygiea’s spherical shape and family can be explained by a collision with a large projectile (diameter ~75–150 km). By comparing Hygiea’s sphericity with that of other Solar System objects, it appears that Hygiea is nearly as spherical as Ceres, opening up the possibility for this object to be reclassified as a dwarf planet. © 2019, The Author(s), under exclusive licence to Springer Nature Limited., P.V., A.D. and B.C. were supported by CNRS/INSU/PNP. M.Broz was supported by grant 18-04514J of the Czech Science Foundation. J.H. and J.D. were supported by grant 18-09470S of the Czech Science Foundation and by the Charles University Research Programme no. UNCE/SCI/023. This project has received funding from the European Union's Horizon 2020 research and innovation programmes under grant agreement nos 730890 and 687378. This material reflects only the authors' views, and the European Commission is not liable for any use that may be made of the information contained herein. TRAPPIST-North is a project funded by the University of Liege, in collaboration with Cadi Ayyad University of Marrakech (Morocco). TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F. E.J. and M.G. are F.R.S.-FNRS Senior Research Associates.
Published: 2019
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22. The shape of (7) Iris as evidence of an ancient large impact?

Author: Miroslav Brož, Philippe Lamy, Anna Marciniak, Josef Ďurech, J. Grice, M. Pajuelo, Paolo Tanga, Patrick Michel, Benoit Carry, Marin Ferrais, Emmanuel Jehin, Bin Yang, Alexis Drouard, Toni Santana-Ros, Frédéric Vachier, Franck Marchis, Michael Marsset, Matti Viikinkoski, Josef Hanus, Romain Fétick, Olivier Witasse, Christophe Dumas, J. Berthier, François Colas, Julie Castillo-Rogez, Agnieszka Kryszczyńska, Tadeusz Michalowski, Mikko Kaasalainen, Grzegorz Dudziński, Pierre Vernazza, Przemyslaw Bartczak, E. Podlewska-Gaca, Mirel Birlan, Thierry Fusco, H. Le Coroller, Arthur Vigan, Laurent Jorda, Fabrice Cipriani, Astronomical Institute of Charles University, Charles University [Prague] (CU), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), 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), Department of Mathematics [Tampere], Tampere University of Technology [Tampere] (TUT), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Search for Extraterrestrial Intelligence Institute (SETI), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), West Pomeranian University of Technology in Szczecin (ZUT), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, The Open University [Milton Keynes] (OU), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), TMT International Observatory, Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), 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), Technical University of Szczecin (TUNIV), Technical university of Szczecin, European Space Agency (ESA), TMT Observatory, and Pontificia Universidad Católica del Perú (PUCP)
Subjects: Solar System, Planetesimal, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, methods: numerical, Impact crater, Angular diameter, 0103 physical sciences, medicine, Iris (anatomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Collisional family, Astronomy and Astrophysics, 15. Life on land, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], minor planets, asteroids: individual: 7 Iris, methods: observational, Astrophysics - Earth and Planetary Astrophysics
Abstract: Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V$\sim$7-8) and large angular size of 0.33 arcsec during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100 Myr of the solar system's collisional evolution. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE as inputs. We analyzed the SPHERE images to infer the asteroid's global shape and the morphology of its main craters. We present the volume-equivalent diameter D$_{{\rm eq}}$=214$\pm$5 km, and bulk density $\rho$=2.7$\pm$0.3 g cm$^{-3}$ of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20--40 km in diameter detected at several epochs, which we interpret as impact craters. Craters on Iris have depth-to-diameter ratios that are similar to those of analogous 10 km craters on Vesta. The bulk density of Iris is consistent with that of its meteoritic analog, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3 Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities., Comment: Accepted for publication in Astronomy and Astrophysics
Published: 2019
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23. Homogeneous internal structure of CM-like asteroid (41) Daphne

Author: Arthur Vigan, Agnieszka Kryszczyńska, Josef Hanus, Clark R. Chapman, Al Conrad, Eric Lagadec, Emmanuel Jehin, B. L. Enke, Michaël Gillon, Matti Viikinkoski, Pierre Vernazza, A. Marciniak, Bin Yang, Marin Ferrais, L. Bernasconi, Miriam Keppler, William J. Merline, Alexis Drouard, Alice Zurlo, Olivier Witasse, J. Grice, Peter Tamblyn, Michael Marsset, Benoit Carry, Romain Fétick, Jérôme Berthier, S. Fauvaud, Christophe Dumas, Frédéric Vachier, F. Marchis, P. Bartczak, François Colas, Agnes Fienga, Tadeusz Michalowski, Julie Castillo-Rogez, Toni Santana-Ros, Brian D. Warner, P. Lamy, Laurent Jorda, Josef Ďurech, P. Michel, Mirel Birlan, Thierry Fusco, Zouhair Benkhaldoun, E. Podlewska-Gaca, Fabrice Cipriani, Jack D. Drummond, Mikko Kaasalainen, Raoul Behrend, M. Pajuelo, Paolo Tanga, Tampere University, Computing Sciences, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), 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), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), University of Arizona, Adam Mickiewicz University in Poznań (UAM), West Pomeranian University of Technology in Szczecin (ZUT), Astronomical Observatory [Poznan], Tampere University of Technology [Tampere] (TUT), Charles University [Prague] (CU), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Starfire Optical Range [AFRL] (SOR), United States Air Force (USAF), Binary Astronomy, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Courbes de rotation d'astéroïdes, de comètes et d'étoiles variables (CdR & CdL group), CdR & CdL group, Université Cadi Ayyad [Marrakech] (UCA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astronomical Institute of Charles University, Observatoire du Bois de Bardon, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut d'Astrophysique et de Géophysique [Liège], Department of Mathematics [Tampere], Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Fundació Privada Observatori Esteve Duran, Amgen (Europe) GmbH, Center for Solar System Studies (CS3), Research and Scientific Support Department of ESA, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Universidad Diego Portales [Santiago] (UDP), ESO programs 281.C-5011 099.D-0098 199.C-0074(AFonds de la Recherche Scientifique - FNRS FRFC 2.5.594.09National Aeronautics & Space Administration (NASA) NCC 5-538National Aeronautics & Space Administration (NASA) 09-NEOO009-0001National Science Foundation (NSF) 0506716 0907766, European Project: 69W4518(1969), 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), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Technical university of Szczecin, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Genève (UNIGE), European Space Agency (ESA), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA), Observatoire de la Côte d'Azur (OCA), Centre National de la Recherche Scientifique (CNRS), Charles University [Prague], Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], and ONERA-Université Paris-Saclay
Subjects: 010504 meteorology & atmospheric sciences, Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Impact crater, 0103 physical sciences, 111 Mathematics, observational [Daphne methods], education, 010303 astronomy & astrophysics, asteroids: individual: Daphne, 0105 earth and related environmental sciences, individual: [minor planets, asteroids], Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], education.field_of_study, Very Large Telescope, high angular resolution [techniques], techniques: high angular resolution, Astronomy and Astrophysics, asteroids: general, Orbit, Space and Planetary Science, Asteroid, minor planets, Asteroid belt, Satellite, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [minor planets, asteroids], Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy and numerical modeling of their early thermal evolution. Aims: Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. Methods: We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3D shape, using our ADAM shape modeling algorithm. Results: The satellite orbits Daphne on an equatorial, quasi- circular, prograde orbit, like the satellites of many other large main- belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77 ¬± 0.26 g cm-3 (3 œÉ). This densityis consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (‚âà 17%). Conclusions: Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous. Based on observations made with (1) ESO Telescopes at the La Silla Paranal Observatory under programs http://281.C-5011 (PI Dumas), http://099.D-0098 (SPHERE GTO), and h ttp://199.C-0074(A) (PI Vernazza); and (2) the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.The reduced and deconvolved AO images and the 3D shape model are publicly available at h ttp://observations.lam.fr/astero/ and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/qcat?J/A+A/623/A132
Published: 2019
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24. Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE

Author: Olivier Witasse, Tadeusz Michalowski, Anna Marciniak, J. Berthier, Benoit Carry, Benoit Neichel, Arthur Vigan, Michael Marsset, E. Podlewska-Gaca, Marin Ferrais, P. Lamy, Laurent Jorda, Pierre Vernazza, Toni Santana-Ros, Bin Yang, Josef Hanus, Matti Viikinkoski, Franck Marchis, Frédéric Vachier, Przemyslaw Bartczak, Christophe Dumas, Mirel Birlan, R. Jl. Fétick, François Colas, Julie Castillo-Rogez, Patrick Michel, Laurent M. Mugnier, Agnieszka Kryszczyńska, M. Pajuelo, Paolo Tanga, H. Le Coroller, Fabrice Cipriani, Thierry Fusco, Alexis Drouard, Mikko Kaasalainen, Grzegorz Dudziński, Emmanuel Jehin, 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), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Fundació Privada Observatori Esteve Duran, Charles University [Prague], Tampere University of Technology [Tampere] (TUT), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Adam Mickiewicz University in Poznań (UAM), Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université de Liège, Institut d'Astrophysique et de Géophysique [Liège], Department of Mathematics [Tampere], Astronomical Observatory [Poznan], Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Amgen (Europe) GmbH, Galaxies, Etoiles, Physique, Instrumentation (GEPI), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica del Perú (PUCP), Universisty of Szczecin (Szczecin) (Institute of Physics), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Tampere University, Computing Sciences, DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), 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), Charles University [Prague] (CU), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Szczecin, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), European Space Astronomy Centre (ESAC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Nanophysique Magnétisme et Optoélectronique (LNMO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
Subjects: Point spread function, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), techniques: image processing, Astrophysics, 01 natural sciences, Interplanetary mission, Observatory, 0103 physical sciences, 111 Mathematics, 010303 astronomy & astrophysics, Image resolution, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), techniques: high angular resolution, Astronomy and Astrophysics, asteroids: individual: Vesta, Albedo, 13. Climate action, Space and Planetary Science, Asteroid, minor planets, methods: observational, Interplanetary spaceflight, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; Context. Over the past decades, several interplanetary missions have studied small bodies in situ, leading to major advances in our understanding of their geological and geophysical properties. These missions, however, have had a limited number of targets. Among them, the NASA Dawn mission has characterised in detail the topography and albedo variegation across the surface of asteroid (4) Vesta down to a spatial resolution of 20 m pixel-1 scale. Aims: Here our aim was to determine how much topographic and albedo information can be retrieved from the ground with VLT/SPHERE in the case of Vesta, having a former space mission (Dawn) providing us with the ground truth that can be used as a benchmark. Methods: We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO large programme (ID 199.C-0074) at six different epochs, and deconvolved the collected images with a parametric point spread function (PSF). We then compared our images with synthetic views of Vesta generated from the 3D shape model of the Dawn mission, on which we projected Vesta's albedo information. Results: We show that the deconvolution of the VLT/SPHERE images with a parametric PSF allows the retrieval of the main topographic and albedo features present across the surface of Vesta down to a spatial resolution of 20-30 km. Contour extraction shows an accuracy of 1 pixel (3.6 mas). The present study provides the very first quantitative estimate of the accuracy of ground-based adaptive-optics imaging observations of asteroid surfaces. Conclusions: In the case of Vesta, the upcoming generation of 30-40 m telescopes (ELT, TMT, GMT) should in principle be able to resolve all of the main features present across its surface, including the troughs and the north-south crater dichotomy, provided that they operate at the diffraction limit. Reduced images of Table A.1 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/623/A6Based on observations made with ESO Telescopes at the Paranal Observatory under programme ID 199.C-0074 (PI: P. Vernazza).
Published: 2019
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25. A photochemical model of the dust-loaded ionosphere of Mars

Author: Mary Michael, Gregorio J. Molina-Cuberos, Franck Montmessin, Olivier Witasse, Grégoire Déprez, Keran O'Brien, Sachchida Nand Tripathi, and Sandy Cardnell
Subjects: Physics, Range (particle radiation), 010504 meteorology & atmospheric sciences, Schumann resonances, Atmosphere of Mars, Mars Exploration Program, Photochemistry, Atmospheric sciences, 01 natural sciences, Aerosol, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Ionization, Physics::Space Physics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Astrophysics::Earth and Planetary Astrophysics, Atmospheric electricity, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The ionization of the lower Martian atmosphere and the presence of charged species are fundamental in the understanding of atmospheric electricity phenomena, such as electric discharges, large scale electric currents and Schumann resonances. The present photochemical model of the lower ionosphere of Mars (0–70 km) is developed to compute the concentration of the most abundant charged species (cluster-ions, electrons and charged aerosols) and electric conductivity, at the landing site and epoch of the ExoMars 2016 mission. The main sources of ionization are galactic cosmic rays (during daytime as well as nighttime) and photoionization of aerosols due to solar UV radiation during daytime. Ion and electron attachment to aerosols is another major source of aerosol charging. The steady state concentration of charged species is computed by solving their respective balance equations (also known as continuity equations), which include the source and sink terms of their photochemical reactions. Since the amount of suspended dust can vary considerably and it has an important effect on atmospheric properties, several dust scenarios, in addition to the day-night variations, are considered to characterize the variability of the concentration of charged species. It has been found that, during daytime, aerosols tend to become positively charged due to electron photoemission, and during nighttime, tend to charge negatively due to electron attachment. The most dominant day-night variability in ion and electron concentration occurs when the amount of suspended dust is the largest. The electric conductivity has been found to vary in the 10−13–10−7 S/m range, depending on the altitude, dust scenario and local time.
Published: 2016
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26. Cold atom gravimetry for planetary missions

Author: Fabian Müller, Pieter Visser, Olivier Carraz, and Olivier Witasse
Subjects: Physics, Earth's orbit, 010504 meteorology & atmospheric sciences, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Mars Exploration Program, Scale factor, 01 natural sciences, Computational physics, Interferometry, Orders of magnitude (time), Gravitational field, Space and Planetary Science, 0103 physical sciences, Orbit (dynamics), Astrophysics::Earth and Planetary Astrophysics, Gravimetry, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Cold Atom Interferometry (CAI) is a promising new technology for gravity missions, enabling measurements with a potential error level that is several orders of magnitude lower compared to classical electro-static accelerometers. Whereas the latter typically suffer from high noise at low frequencies, with biases and scale factor instabilities, cold atom interferometers give an absolute measurement and are highly accurate over the entire frequency range. Especially for planetary missions, drift-free cold atom interferometry can be highly beneficial, because it does not need any on-board calibration. In this work we present the improvement of using a CAI instrument, with respect to classic Doppler-tracking technique, to retrieve the gravity field of Venus and Mars. In order to estimate the performances with many parameters (orbit altitude, mission duration, sensitivity) a scalar scale factor is proposed to fit a simulated CAI instrument on Earth orbit to other celestial bodies. The spherical harmonic degree strength of the gravitational field retrieval is estimated and the results presented here agree with Fast Error Propagation Tools.
Published: 2020
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27. The chemical composition of impact craters on Titan

Author: Ioannis Baziotis, Ashley Schoenfeld, Olivier Witasse, Catherine D. Neish, Kenneth J. Lawrence, Alyssa Werynski, Athena Coustenis, Nicolas Altobelli, Michael Malaska, R. M. C. Lopes, A. Solomonidou, Pierre Drossart, Christos Matsoukas, Yannis Markonis, and A. Le Gall
Subjects: Physics, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Alluvial fan, Fluvial, Astronomy and Astrophysics, Tholin, Astrophysics, 15. Life on land, 01 natural sciences, Astrobiology, symbols.namesake, Impact crater, 13. Climate action, Space and Planetary Science, 0103 physical sciences, symbols, Ejecta blanket, Titan (rocket family), Ejecta, 010303 astronomy & astrophysics, Chemical composition, 0105 earth and related environmental sciences
Abstract: We investigate the spectral behavior of nine Titan impact craters in order to constrain their composition. Past studies that have examined the chemical composition of impact craters on Titan have either used qualitative comparisons between craters or combined all craters into a single unit, rather than separating them by geographic location and/or degradation state. Here, we use Visual and Infrared Mapping Spectrometer (VIMS) data and a radiative transfer code to estimate the atmospheric contribution to the data, extract the surface albedos of the impact craters, and constrain their composition by using a library of candidate Titan materials, including essentially water ice, tholin, a dark component, and other possible ices at different grain sizes. Following a general characterization of the impact craters, we study two impact crater subunits, the “crater floor” and the “ejecta blanket”. The results show that the equatorial dune craters – Selk, Ksa, Guabonito, and the crater on Santorini Facula – appear to be purely composed of organic material (mainly an unknown dark component). Titan’s midlatitude plain craters – Afekan, Soi, and Forseti – along with Menrva and Sinlap, are enriched in water ice within an organic-based mixture. This follows the geographic pattern observed in our previous work with VIMS data, where the uppermost layers of the midlatitude alluvial fans, undifferentiated plains, and labyrinth terrains were found to consist of a mixture of organics and water ice, while the equatorial plains, hummocky terrains, and dunes were found to consist of a mixture of dark material and tholins. Furthermore, we found that the addition of some form of ice improves the fit in the ejecta spectra of Afekan and Sinlap craters. We find no indication for the presence of either NH3 or CO2 ice. Our main results agree with an existing Titan surface evolution scenario, wherein the impact cratering process produces a mixture of organic material and water ice, which is later “cleaned” through fluvial erosion in the midlatitude plains. This cleaning process does not appear to operate in the equatorial regions, which are quickly covered by a thin layer of sand sediment (with the exception of the freshest crater on Titan, Sinlap). Thus, it appears that active processes are working to shape the surface of Titan, and it remains a dynamic world in the present day.
Published: 2020
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28. Spectral and emissivity analysis of the raised ramparts around Titan's northern lakes

Author: Olivier Witasse, R. J. Michaelides, S. D. Wall, A. Le Gall, Jason M. Soderblom, Pierre Drossart, Athena Coustenis, Charles Elachi, Kenneth J. Lawrence, Samuel Birch, Christos Matsoukas, A. Solomonidou, J. Yates, Maya Nasr, Jani Radebaugh, Alexander G. Hayes, R. M. C. Lopes, Michael Malaska, M. A. Janssen, Sebastien Rodriguez, Ashley Schoenfeld, European Space Astronomy Centre (ESAC), European Space Agency (ESA), California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Cornell University [New York], Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Physics Department [Stanford], Stanford University, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Royal Institute of Technology [Stockholm] (KTH ), European Space Research and Technology Centre (ESTEC), Department of Geological Sciences [BYU], Brigham Young University (BYU), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Cornell University, Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Department of Physics [Stanford], and Stanford University [Stanford]
Subjects: Titan hydrology, 010504 meteorology & atmospheric sciences, Terrain, 01 natural sciences, law.invention, symbols.namesake, law, 0103 physical sciences, Radiative transfer, Emissivity, Radar, 010303 astronomy & astrophysics, Spectroscopy, 0105 earth and related environmental sciences, Remote sensing, Shore, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Northern Hemisphere, Astronomy and Astrophysics, Radar observations, 13. Climate action, Space and Planetary Science, Titan surface, symbols, Radiometry, Titan (rocket family), Geology
Abstract: International audience; Some of Titan's small northern hemisphere lakes show raised rampart features (which are distinct from raised rims), and appear as SAR-bright mound-like annuli extending away from the lake for up to tens of kilometers from the shoreline. We investigate the infrared and microwave characteristics of these features using Cassini Visual and Infrared Mapping Spectrometer (VIMS) and RADAR data. A spectral comparative analysis is performed among the lakes, their ramparts, and the surrounding regions. We overcome the profound difference in spatial resolution between VIMS and SAR data by using a method that provides overlays between the spectral images and SAR, thus enabling the correct selection of VIMS pixels. The surface properties of the selected areas are obtained using a radiative transfer analysis on the selected VIMS pixels, in addition to emissivity obtained from the RADAR in radiometry mode. Analysis of these combined and co-registered data provides constraints for the formation mechanism(s) of raised ramparts. The results show that the emissivity of the raised ramparts is close to that of Titan's labyrinthic terrains and to that of empty lake floors in the northern polar regions. This is confirmed by the VIMS analysis that also shows that the infrared spectral response of the raised ramparts is very similar to that of some empty lake floors. This suggests that both areas are made from or are covered by a similar material. In addition, two out of the eight lakes with raised ramparts show spectral differences at three specific wavelengths, 1.6, 2.0, and 5.0 μm, between the ramparts and the surrounding terrain. We hypothesize that this could be due to some component, or mixture of components in the ramparts that is less absorbent at these specific wavelengths, or it could be an effect of different grain sizes. These observations provide first insights into the possible mechanisms leading to the formation of the raised ramparts that are discussed here.
Published: 2020
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29. MoMo: a new empirical model of the Mars ionospheric total electron content based on Mars Express MARSIS data

Author: Kerstin Peter, Jean-Marie Chevalier, Véronique Dehant, Nicolas Bergeot, Wlodek Kofman, Sébastien Le Maistre, Pierre-Louis Blelly, Olivier Witasse, Solar-Terrestrial Centre of Excellence [Brussels] (STCE), Royal Observatory of Belgium [Brussels] (ROB), Université Catholique de Louvain = Catholic University of Louvain (UCL), European Space Agency (ESA), 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), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Agence Spatiale Européenne = European Space Agency (ESA), 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), and UCL - SST/ELI/ELIC - Earth & Climate
Subjects: Martian, Atmospheric Science, 010504 meteorology & atmospheric sciences, Total electron content, Solar zenith angle, MARSIS, Mars Exploration Program, lcsh:QC851-999, 01 natural sciences, Physics::Geophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Martian surface, 0103 physical sciences, Physics::Space Physics, Radio occultation, lcsh:Meteorology. Climatology, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract: Aims: Several scientific landers and rovers have reached the Martian surface since the 1970s. Communication between the asset (i.e., lander or rover) and Mars orbiters or Earth antennas uses radio signals in UHF to X-band frequencies passing through the Mars’ ionosphere. It is consequently necessary to take into account electron density variation in the Mars’ ionosphere to correct the refraction of the signal transmitted. Methods: We developed a new empirical model of the Mars’ ionosphere called MoMo. It is based on the large database of Total Electron Content (TEC) derived from the subsurface mode of the Mars Express MARSIS radar. The model provides vertical TEC as a function of solar zenith angle, solar activity, solar longitude and location. For validation, the model is compared with Mars Express radio occultation data as well as with the numerical model IPIM (IRAP Plasmasphere-Ionosphere Model). Results: We discussed the output of the model in terms of climatology behaviour of the Mars’ ionosphere. The output of MoMo is then uses to quantify the impact of the Martian ionosphere for radio-science experiments. From our results, the effect is of the order of 10−3 mm s−1 in Doppler observables especially around sunrise and sunset. Consequently, this new model could be used to support the data analysis of any radio-science experiment and especially for present InSight RISE and futur ExoMars LARA instruments aiming at better understand the deep-interior of Mars.
Published: 2019
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30. Transplanet: A web service dedicated to modeling of planetary ionospheres

Author: Olivier Witasse, P.-L. Blelly, Jorge Amaya, M. Bouchemit, N. André, Aurélie Marchaudon, B. Chide, M. Indurain, Vincent Génot, A. Goutenoir, Institut de recherche en astrophysique et planétologie (IRAP), 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Centre for Plasma Astrophysics [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), 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), and European Space Agency (ESA)-European Space Agency (ESA)
Subjects: Service (systems architecture), Data processing, 010504 meteorology & atmospheric sciences, Interface (Java), Computer science, business.industry, Distributed computing, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Mars Exploration Program, Virtual observatory, Modular design, computer.software_genre, 01 natural sciences, 13. Climate action, Space and Planetary Science, User control, Physics::Space Physics, 0103 physical sciences, Web service, business, 010303 astronomy & astrophysics, computer, 0105 earth and related environmental sciences
Abstract: International audience; We present a new web service (http://transplanet.irap.omp.eu/) dedicated to the modeling of planetary iono-spheres. Thanks to the development made for IRAP ionospheric model IPIM, it uses a unified description of the different ionized environments (presently Venus, Earth, Mars and Jupiter). The service provides a complete set of parameters characterizing these environments, including the concentration, velocities, temperatures, production rates of the different ions and electron heating rates. It is based on a modular approach allowing for selection of species, date of simulation and location. It is intended to be a support tool to data processing and analysis and we describe how simulation results can be used for such a purpose. The output format has been chosen to ease the interface with external data processing or vizualization tools, including online services. This web service is an open service which aims at providing users with the most relevant and consistent description of the couplings in planetary space environments and it will evolve in a way to increase user control on the simulation through a simplified Human-machine interface (HMI).
Published: 2019
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31. (16) Psyche: A mesosiderite-like asteroid?

Author: Tadeusz Michalowski, P. Bartczak, J. Grice, Brian D. Warner, Christophe Dumas, Frédéric Vachier, Laurent Jorda, Josef Hanus, Olivier Witasse, Alexis Drouard, E. Podlewska-Gaca, Fabrice Cipriani, Romain Fétick, François Colas, Julie Castillo-Rogez, Philippe Lamy, F. Marchis, Marin Ferrais, Emmanuel Jehin, Jérôme Berthier, Josef Ďurech, P. Michel, A. Marciniak, Arthur Vigan, Pierre Vernazza, H. Le Coroller, Thierry Fusco, Bin Yang, Michael Marsset, Mirel Birlan, Toni Santana-Ros, Benoit Carry, Matti Viikinkoski, Agnieszka Kryszczyńska, Mikko Kaasalainen, K. Tazhenova, M. Pajuelo, Paolo Tanga, Tampere University of Technology [Tampere] (TUT), 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), Astronomical Institute of Charles University, Charles University [Prague] (CU), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Search for Extraterrestrial Intelligence Institute (SETI), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Faculty of Physics [Poznań], Adam Mickiewicz University in Poznań (UAM), TMT International Observatory, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Open University (School of Physical Sciences), 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), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), University of Szczecin, Center for Solar System Studies (CS3), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), 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), TMT Observatory, European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Pontificia Universidad Católica del Perú (PUCP)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectral properties, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, 01 natural sciences, Parent body, Psyche, Mesosiderite, Meteorite, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Hill sphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: Asteroid (16) Psyche is the target of the NASA Psyche mission. It is considered one of the few main-belt bodies that could be an exposed proto-planetary metallic core and that would thus be related to iron meteorites. Such an association is however challenged by both its near- and mid-infrared spectral properties and the reported estimates of its density. Here, we aim to refine the density of (16) Psyche to set further constraints on its bulk composition and determine its potential meteoritic analog. We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large program (ID 199.C-0074). We used the high angular resolution of these observations to refine Psyche's three-dimensional (3D) shape model and subsequently its density when combined with the most recent mass estimates. In addition, we searched for potential companions around the asteroid. We derived a bulk density of 3.99\,$\pm$\,0.26\,g$\cdot$cm$^{-3}$ for Psyche. While such density is incompatible at the 3-sigma level with any iron meteorites ($\sim$7.8\,g$\cdot$cm$^{-3}$), it appears fully consistent with that of stony-iron meteorites such as mesosiderites (density $\sim$4.25\,$\cdot$cm$^{-3}$). In addition, we found no satellite in our images and set an upper limit on the diameter of any non-detected satellite of 1460\,$\pm$\,200}\,m at 150\,km from Psyche (0.2\%\,$\times$\,R$_{Hill}$, the Hill radius) and 800\,$\pm$\,200\,m at 2,000\,km (3\%\,$\times$\,$R_{Hill}$). Considering that the visible and near-infrared spectral properties of mesosiderites are similar to those of Psyche, there is merit to a long-published initial hypothesis that Psyche could be a plausible candidate parent body for mesosiderites., 16 pages
Published: 2018
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32. The DREAMS Experiment Onboard the Schiaparelli Module of the ExoMars 2016 Mission: Design, Performances and Expected Results

Author: F. Valero, Giacomo Colombatti, François Forget, Maria Genzer, J. J. Jiménez, Ernesto Palomba, Alessio Aboudan, T. Nikkanen, Ralph D. Lorenz, John Robert Brucato, Nilton O. Renno, F. J. Álvarez, J. Martinez-Oter, Daniel Toledo, Ciprian Ionut Popa, Ari-Matti Harri, I. Arruego Rodríguez, Vito Mennella, Simone Silvestro, Maria Hieta, Jean-Pierre Pommereau, Giancarlo Bellucci, Simone Pirrotta, Pietro Schipani, Franck Montmessin, Luis Vázquez, R. Molinaro, Francesca Esposito, Harri Haukka, G. Landis, G. Déprez, D. Moirin, Francesca Ferri, Jean-Jacques Berthelier, Stefano Debei, Natalia Deniskina, L. Lapauw, O. Karatekin, Fausto Cortecchia, F. Cucciarrè, G. Di Achille, Gabriele Franzese, Aymeric Spiga, Sebastiano Chiodini, Raffaele Mugnuolo, Cesare Molfese, E. Marchetti, Olivier Witasse, Jean-Luc Josset, S. B. Calcutt, Colin Wilson, V. Apestigue, Margarita Yela, F. Vivat, Pascal Rannou, Enrico Friso, D. Möhlmann, Laurent Marty, R. Hassen-Kodja, S. Rafkin, Manish R. Patel, J. Rivas, Walter Schmidt, Fabio Cozzolino, E. Segato, Roland Trautner, Henrik Kahanpää, Carlo Bettanini, INAF - Osservatorio Astronomico di Capodimonte (OAC), Istituto Nazionale di Astrofisica (INAF), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Instituto Nacional de Técnica Aeroespacial (INTA), Finnish Meteorological Institute (FMI), 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), University of Oxford [Oxford], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), INAF - Osservatorio Astrofisico di Arcetri (OAA), INAF - Osservatorio Astronomico di Bologna (OABO), Osservatorio Astronomico d'Abruzzo, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Dipartimento di Fisica 'Ettore Pancini', Università degli studi di Napoli Federico II, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Exploration Institute [Neuchâtel] (SPACE - X), Royal Observatory of Belgium [Brussels] (ROB), NASA Glenn Research Center, NASA, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), The Open University [Milton Keynes] (OU), STRATO - LATMOS, Southwest Research Institute [San Antonio] (SwRI), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), University of Michigan [Ann Arbor], University of Michigan System, Université de Reims Champagne-Ardenne (URCA), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Departamento de Astrofisica y Ciencias de la Atmósfera, Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), Agenzia Spaziale Italiana (ASI), ITA, USA, GBR, FRA, DEU, ESP, BEL, FIN, NLD, and CHE
Subjects: Meridiani Planum, 010504 meteorology & atmospheric sciences, Computer science, Mars, 01 natural sciences, law.invention, Orbiter, law, Dust storm season, 0103 physical sciences, Aerospace engineering, 010303 astronomy & astrophysics, DREAMS, 0105 earth and related environmental sciences, Martian, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Payload, Atmospheric electric field, ExoMars, Meteorological station, Schiaparelli, Astronomy and Astrophysics, Space and Planetary Science, Touchdown, Atmosphere of Mars, Mars Exploration Program, Spare part, business
Abstract: International audience; The first of the two missions foreseen in the ExoMars program was successfully launched on 14th March 2016. It included the Trace Gas Orbiter and the Schiaparelli Entry descent and landing Demonstrator Module. Schiaparelli hosted the DREAMS instrument suite that was the only scientific payload designed to operate after the touchdown. DREAMS is a meteorological station with the capability of measuring the electric properties of the Martian atmosphere. It was a completely autonomous instrument, relying on its internal battery for the power supply. Even with low resources (mass, energy), DREAMS would be able to perform novel measurements on Mars (atmospheric electric field) and further our understanding of the Martian environment, including the dust cycle. DREAMS sensors were designed to operate in a very dusty environment, because the experiment was designed to operate on Mars during the dust storm season (October 2016 in Meridiani Planum). Unfortunately, the Schiaparelli module failed part of the descent and the landing and crashed onto the surface of Mars. Nevertheless, several seconds before the crash, the module central computer switched the DREAMS instrument on, and sent back housekeeping data indicating that the DREAMS sensors were performing nominally. This article describes the instrument in terms of scientific goals, design, working principle and performances, as well as the results of calibration and field tests. The spare model is mature and available to fly in a future mission.
Published: 2018
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33. Energetic Particle Showers Over Mars from Comet C/2013 A1 Siding Spring

Author: Mark Lester, Stephen E. Milan, Beatriz Sánchez – Cano, Robert Lillis, Olivier Witasse, Stanley W. H. Cowley, Christina O. Lee, Jeffrey J. Plaut, Ali Rahmati, Jared Espley, Pierre-Louis Blelly, Richard M. Ambrosi, M. Costa, Davin Larson, François Leblanc, Radio and Space Plasma Physics Group [Leicester] (RSPP), University of Leicester, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), HELIOS - 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), Institut de recherche en astrophysique et planétologie (IRAP), 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), European Space Astronomy Centre (ESAC), GSFC Planetary Magnetospheres Laboratory, NASA Goddard Space Flight Center (GSFC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Agency (ESA), University of California [Berkeley], University of California-University of California, 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 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), and California Institute of Technology (CALTECH)-NASA
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Comet, Mars Exploration Program, Atmosphere of Mars, Space weather, 01 natural sciences, Astrobiology, Atmosphere, Solar wind, Geophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Particle, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; This paper is a phenomenological description of multi‐spacecraft observations of energetic particles caused by the close flyby of comet C/2013 A1 Siding‐Spring with Mars on 19 October 2014. This is the first time that cometary energetic particles have been observed at Mars. The Mars Atmosphere and Volatile EvolutioN (MAVEN) Solar Energetic Particle (SEP) and the Mars Odyssey High Energy Neutron Detector (HEND) instruments recorded evidence of precipitating particles, that are likely O+ pick‐up ions, during the ~10 hours that Mars was within the region of the comet's coma. O+ pick‐up ions were also detected several hours after, although whether their origin is the comet or space weather is not conclusive. We discuss the possible origin of those particles, and also, the cause of an additional shower of energetic particles that HEND observed between 22 and 35 h after the comet's closest approach, which may be related to dust impacts from the comet's dust tail. An O+ pick‐up ion energy flux simulation is performed with representative solar wind and cometary conditions, together with a simulation of their energy deposition profile in the atmosphere of Mars. Results indicate that the O+ pick‐up ion fluxes observed by SEP were deposited in the ionosphere around 105‐120 km altitude, and they are compared with pre‐comet flyby estimations of cometary pick‐up ions. The comet's flyby deposited a significant fluence of energetic particles into Mars' upper atmosphere, at a similar level to a large space weather event.
Published: 2018
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34. Modeling the Evolution and Propagation of 10 September 2017 CMEs and SEPs Arriving at Mars Constrained by Remote Sensing and In Situ Measurement

Author: Jingnan Guo, Cary Zeitlin, Bent Ehresmann, Henning Lohf, Astrid Veronig, Robert F. Wimmer-Schweingruber, Mateja Dumbović, Leila Mays, Mats Holmström, Donald M. Hassler, Olivier Witasse, Johan L. Freiherr von Forstner, Yuming Wang, Bernd Heber, Manuela Temmer, and Arik Posner
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Solar energetic particles, Mars Exploration Program, Geophysics, Space weather, Radiation assessment detector, 01 natural sciences, law.invention, 13. Climate action, law, 0103 physical sciences, Forbush decrease, Interplanetary spaceflight, 010303 astronomy & astrophysics, Coronagraph, Heliosphere, Geology, 0105 earth and related environmental sciences, coronal mass ejection (CME), interplanetary shock, solar energetic particle (SEP), ground level enhancement (GLE), planetary space weather, multispacecraft measurement, Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics
Abstract: On 10 September 2017, solar energetic particles originating from the active region 12673 produced a ground level enhancement at Earth. The ground level enhancement on the surface of Mars, 160 longitudinally east of Earth, observed by the Radiation Assessment Detector (RAD) was the largest since the landing of the Curiosity rover in August 2012. Based on multipoint coronagraph images and the Graduated Cylindrical Shell model, we identify the initial 3-D kinematics of an extremely fast coronal mass ejection (CME) and its shock front, as well as another two CMEs launched hours earlier with moderate speeds. The three CMEs interacted as they propagated outward into the heliosphere and merged into a complex interplanetary CME (ICME). The arrival of the shock and ICME at Mars caused a very significant Forbush decrease seen by RAD only a few hours later than that at Earth, which was about 0.5 AU closer to the Sun. We investigate the propagation of the three CMEs and the merged ICME together with the shock, using the drag-based model and the WSA-ENLIL plus cone model constrained by the in situ observations. The synergistic study of the ICME and solar energetic particle arrivals at Earth and Mars suggests that to better predict potentially hazardous space weather impacts at Earth and other heliospheric locations for human exploration missions, it is essential to analyze (1) the eruption of the flare and CME at the Sun, (2) the CME kinematics, especially during their interactions, and (3) the spatially and temporally varying heliospheric conditions, such as the evolution and propagation of the stream interaction regions.
Published: 2018
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35. The Spectral Nature of Titan's Major Geomorphological Units: Constraints on Surface Composition

Author: Bernard Schmitt, S. D. Wall, S. Philippe, Emmanuel Bratsolis, Christophe Sotin, S. Le Mouélic, Olivier Witasse, A. Solomonidou, Katrin Stephan, Rosaly M. C. Lopes, Charles Elachi, A. Le Gall, Jani Radebaugh, E. Villanueva, A. Anthony Bloom, M. Hirtzig, Robert H. Brown, Athena Coustenis, Kenneth J. Lawrence, Christos Matsoukas, Nicolas Altobelli, M. A. Janssen, Michael Malaska, Pierre Drossart, Sebastien Rodriguez, Jérémy F. Brossier, Ashley Schoenfeld, 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), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Fondation La main à la pâte, Department of Physics [Athens], National and Kapodistrian University of Athens = University of Athens (NKUA | UoA), Department of Geological Sciences [BYU], Brigham Young University (BYU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Royal Institute of Technology [Stockholm] (KTH ), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, 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), Agence Spatiale Européenne = European Space Agency (ESA), NASA-California Institute of Technology (CALTECH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), National and Kapodistrian University of Athens (NKUA), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), University of California (UC)-University of California (UC), and Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Synthetic aperture radar, Haze, 010504 meteorology & atmospheric sciences, Spectral response, Atmospheric sciences, Titan geology, 01 natural sciences, Latitude, symbols.namesake, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Radiative transfer, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], saturnian satellites, Geophysics, 13. Climate action, Space and Planetary Science, radiative transfer, [SDU]Sciences of the Universe [physics], symbols, Evolution theories, Water ice, spectral behavior, geomorphological units, Titan composition, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: We investigate Titan's low‐latitude and midlatitude surface using spectro‐imaging near‐infrared data from Cassini/Visual and Infrared Mapping Spectrometer. We use a radiative transfer code to first evaluate atmospheric contributions and then extract the haze and the surface albedo values of major geomorphological units identified in Cassini Synthetic Aperture Radar data, which exhibit quite similar spectral response to the Visual and Infrared Mapping Spectrometer data. We have identified three main categories of albedo values and spectral shapes, indicating significant differences in the composition among the various areas. We compare with linear mixtures of three components (water ice, tholin‐like, and a dark material) at different grain sizes. Due to the limited spectral information available, we use a simplified model, with which we find that each albedo category of regions of interest can be approximately fitted with simulations composed essentially by one of the three surface candidates. Our fits of the data are overall successful, except in some cases at 0.94, 2.03, and 2.79 μm, indicative of the limitations of our simplistic compositional model and the need for additional components to reproduce Titan's complex surface. Our results show a latitudinal dependence of Titan's surface composition, with water ice being the major constituent at latitudes beyond 30°N and 30°S, while Titan's equatorial region appears to be dominated partly by a tholin‐like or by a very dark unknown material. The albedo differences and similarities among the various geomorphological units give insights on the geological processes affecting Titan's surface and, by implication, its interior. We discuss our results in terms of origin and evolution theories.
Published: 2018
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36. Spatial, Seasonal, and Solar Cycle Variations of the Martian Total Electron Content (TEC): Is the TEC a Good Tracer for Atmospheric Cycles?

Author: Mikel Indurain, Beatriz Sánchez-Cano, Olivier Witasse, Álvaro Vicente-Retortillo, Francisco Gonzalez-Galindo, Marco Cartacci, Raffaella Noschese, Andrea Cicchetti, Pierre-Louis Blelly, Mark Lester, Institut de recherche en astrophysique et planétologie (IRAP), 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), Science and Technology Facilities Council (UK), European Space Agency, Europlanet Society, ITA, GBR, FRA, and ESP
Subjects: Martian, 010504 meteorology & atmospheric sciences, Total electron content, TEC, atmospheric coupling, Ionosphere modeling, Atmospheric sciences, 01 natural sciences, Solar cycle, Atmospheric coupling, Geophysics, Space and Planetary Science, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], TRACER, 0103 physical sciences, Mars express, Earth and Planetary Sciences (miscellaneous), Environmental science, Mars thermosphere, Mars Express, Mars ionosphere, 010303 astronomy & astrophysics, ionosphere modeling, 0105 earth and related environmental sciences
Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited., We analyze 10 years of Mars Express total electron content (TEC) data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument. We describe the spatial, seasonal, and solar cycle behavior of the Martian TEC. Due to orbit evolution, data come mainly from the evening, dusk terminator and postdusk nightside. The annual TEC profile shows a peak at Ls = 25–75° which is not related to the solar irradiance variation but instead coincides with an increase in the thermospheric density, possibly linked with variations in the surface pressure produced by atmospheric cycles such as the CO or water cycles. With the help of numerical modeling, we explore the contribution of the ion species to the TEC and the coupling between the thermosphere and ionosphere. These are the first observations which show that the TEC is a useful parameter, routinely measured by Mars Express, of the dynamics of the lower-upper atmospheric coupling and can be used as tracer for the behavior of the thermosphere.©2018. The Authors., B. S. -C. and M. L. acknowledge support through STFC grant ST/N000749/1. ESA-ESTEC Faculty and Europlanet funding are also gratefully acknowledged. MEX MARSIS RDR and EDR data can be downloaded from the ESA-PSA archive, TIMED-SEE data at the University of Colorado's website (http://lasp.colorado.edu/lisird/index.html), REMS data at the NASA Planetary Data System (http://atmos.nmsu.edu/PDS/data/mslrem_1001/DATA/), the MCD model at the Mars Climate Database web interface (http://www-mars.lmd.jussieu.fr/mars/access.html), and the IPIM model at the IRAP CDPP web interface (http://transplanet.irap.omp.eu/).
Published: 2018
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37. The impact crater at the origin of the Julia family detected with VLT/SPHERE?

Author: Matti Viikinkoski, Toni Santana-Ros, M. Pajuelo, Paolo Tanga, Miroslav Brož, Emmanuel Jehin, Josef Hanus, Zouhair Benkhaldoun, F. Vachier, E. Podlewska-Gaca, Fabrice Cipriani, Bin Yang, Erik Asphaug, Laurent Jorda, Mikko Kaasalainen, Pierre Vernazza, Julie Castillo-Rogez, P. Lamy, Alexis Drouard, Grzegorz Dudziński, Josef Ďurech, P. Michel, Olivier Witasse, Michael Marsset, P. Ševeček, Michaël Gillon, Arthur Vigan, Agnieszka Kryszczyńska, F. Marchis, Jérôme Berthier, P. Bartczak, Thierry Fusco, Benoit Carry, H. Le Coroller, Mirel Birlan, A. Marciniak, Christophe Dumas, Romain Fétick, Tadeusz Michalowski, Derek C. Richardson, Brian D. Warner, F. Colas, Marin Ferrais, 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), Astronomical Institute of Charles University, Charles University [Prague] (CU), Department of Mathematics [Tampere], Tampere University of Technology [Tampere] (TUT), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), 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), Search for Extraterrestrial Intelligence Institute (SETI), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), University of Szczecin, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), TMT Observatory, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica del Perú (PUCP), Center for Solar System Studies (CS3), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), University of Maryland [College Park], University of Maryland System, Université Cadi Ayyad [Marrakech] (UCA), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), TMT International Observatory, Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), Tampere University, and Mathematics
Subjects: Physics, 010504 meteorology & atmospheric sciences, Collisional family, techniques: high angular resolution, asteroids: individual: (89) Julia, Astronomy and Astrophysics, Context (language use), Astrophysics, Asteroid family, 01 natural sciences, Parent body, methods: numerical, Impact crater, Space and Planetary Science, Asteroid, Observatory, 0103 physical sciences, 111 Mathematics, minor planets, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Interplanetary spaceflight, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Context.The vast majority of the geophysical and geological constraints (e.g., internal structure, cratering history) for main-belt asteroids have so far been obtained via dedicated interplanetary missions (e.g., ESA Rosetta, NASA Dawn). The high angular resolution of SPHERE/ZIMPOL, the new-generation visible adaptive-optics camera at ESO VLT, implies that these science objectives can now be investigated from the ground for a large fraction ofD≥ 100 km main-belt asteroids. The sharp images acquired by this instrument can be used to accurately constrain the shape and thus volume of these bodies (hence density when combined with mass estimates) and to characterize the distribution and topography ofD≥ 30 km craters across their surfaces.Aims.Here, via several complementary approaches, we evaluated the recently proposed hypothesis that the S-type asteroid (89) Julia is the parent body of a small compact asteroid family that formed via a cratering collisional event.Methods.We observed (89) Julia with VLT/SPHERE/ZIMPOL throughout its rotation, derived its 3D shape, and performed a reconnaissance and characterization of the largest craters. We also performed numerical simulations to first confirm the existence of the Julia family and to determine its age and the size of the impact crater at its origin. Finally, we utilized the images/3D shape in an attempt to identify the origin location of the small collisional family.Results.On the one hand, our VLT/SPHERE observations reveal the presence of a large crater (D~ 75 km) in Julia’s southern hemisphere. On the other hand, our numerical simulations suggest that (89) Julia was impacted 30–120 Myrs ago by aD~ 8 km asteroid, thereby creating aD≥ 60 km impact crater at the surface of Julia. Given the small size of the impactor, the obliquity of Julia and the particular orientation of the family in the (a,i) space, the imaged impact crater is likely to be the origin of the family.Conclusions.New doors into ground-based asteroid exploration, namely, geophysics and geology, are being opened thanks to the unique capabilities of VLT/SPHERE. Also, the present work may represent the beginning of a new era of asteroid-family studies. In the fields of geophysics, geology, and asteroid family studies, the future will only get brighter with the forthcoming arrival of 30–40 m class telescopes like ELT, TMT, and GMT.
Published: 2018
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38. Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover

Author: Jorge L. Vago, Frances Westall, null Pasteur Instrument Teams, Landing S, Andrew J. Coates, Ralf Jaumann, Oleg Korablev, Valérie Ciarletti, Igor Mitrofanov, Jean-Luc Josset, Maria Cristina De Sanctis, Jean-Pierre Bibring, Fernando Rull, Fred Goesmann, Harald Steininger, Walter Goetz, William Brinckerhoff, Cyril Szopa, François Raulin, Howell G. M. Edwards, Lyle G. Whyte, Alberto G. Fairén, John Bridges, Ernst Hauber, Gian Gabriele Ori, Stephanie Werner, Damien Loizeau, Ruslan O. Kuzmin, Rebecca M. E. Williams, Jessica Flahaut, François Forget, Daniel Rodionov, Håkan Svedhem, Elliot Sefton-Nash, Gerhard Kminek, Leila Lorenzoni, Luc Joudrier, Viktor Mikhailov, Alexander Zashchirinskiy, Sergei Alexashkin, Fabio Calantropio, Andrea Merlo, Pantelis Poulakis, Olivier Witasse, Olivier Bayle, Silvia Bayón, Uwe Meierhenrich, John Carter, Juan Manuel García-Ruiz, Pietro Baglioni, Albert Haldemann, Andrew J. Ball, André Debus, Robert Lindner, Frédéric Haessig, David Monteiro, Roland Trautner, Christoph Voland, Pierre Rebeyre, Duncan Goulty, Frédéric Didot, Stephen Durrant, Eric Zekri, Detlef Koschny, Andrea Toni, Gianfranco Visentin, Martin Zwick, Michel van Winnendael, Martín Azkarate, Christophe Carreau, null the ExoMars Project Team, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Exploration Institute [Neuchâtel] (SPACE - X), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universidad de Valladolid [Valladolid] (UVa), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, NASA Goddard Space Flight Center (GSFC), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Chemical and Forensic Sciences [Bradford], University of Bradford, McGill University = Université McGill [Montréal, Canada], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Research Centre [Leicester], University of Leicester, Freie Universität Berlin, International Research School of Planetary Sciences [Pescara] (IRSPS), Università degli studi 'G. d'Annunzio' Chieti-Pescara [Chieti-Pescara] (Ud'A), Centre for Earth Evolution and Dynamics [Oslo] (CEED), Department of Geosciences [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO)-Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI), Planetary Science Institute [Tucson] (PSI), Institut de recherche en astrophysique et planétologie (IRAP), 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), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Central Scientific Research Institute for Machine Building [Korolev] (TsNIIMASH), Russian Federal Space Agency, NPO S. Lavochkin (Khimki), Thales Alenia Space Italia, Institut de Chimie de Nice (ICN), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Centre National d'Études Spatiales [Toulouse] (CNES), European Space Agency (ESA), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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 d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), 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), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-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), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Chemical and Forensic Sciences, McGill University, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Habitability, Payload, Special Collection of Papers: ExoMars Rover MissionGuest Editor: Jorge L. Vago, Landing sites, Context (language use), Mars Exploration Program, Astrobiology, 01 natural sciences, Agricultural and Biological Sciences (miscellaneous), Mars rover, ExoMars, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Planetengeologie, Search for life, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Biosignature, Biosignatures, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: Finally, we would like to recognize the help and support of ESA, Roscosmos, the European states and agencies participating in the ExoMars program, and NASA. We really are doing this together for the benefit of all., The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information., European Space Agency, Roscosmos, ExoMars program, National Aeronautics & Space Administration (NASA)
Published: 2017
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39. Dications and thermal ions in planetary atmospheric escape

Author: Mathieu Barthelemy, Guillaume Gronoff, Jean Lilensten, Olivier Witasse, C. Simon Wedlund, David Ehrenreich, and Roland Thissen
Subjects: Physics, 010504 meteorology & atmospheric sciences, Atmospheric escape, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, 01 natural sciences, Astrobiology, Atmosphere, Solar wind, 13. Climate action, Space and Planetary Science, Planet, Physics::Space Physics, 0103 physical sciences, Hot Jupiter, Astrophysics::Earth and Planetary Astrophysics, Primary atmosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: In the recent years, the presence of dications in the atmospheres of Mars, Venus, Earth and Titan has been modeled and assessed. These studies also suggested that these ions could participate to the escape of the planetary atmospheres because a large fraction of them is unstable and highly energetic. When they dissociate, their internal energy is transformed into kinetic energy which may be larger than the escape energy. The goal of this study is to assess the impact of the doubly-charged ions in the escape of CO2-dominated planetary atmospheres and to compare it to the escape of thermal photo-ions. We solve a Boltzmann transport equation at daytime taking into account the dissociative states of CO 2 + + for a simplified single constituent atmosphere of a case-study planet. We compute the escape of fast ions using a Beer–Lambert approach. We study three test-cases. On a Mars-analog planet in today’s conditions, we retrieve the measured electron escape flux. When comparing the two mechanisms (i.e. excluding solar wind effects, sputtering, etc.), the escape due to the fast ions issuing from the dissociation of dications may account for up to 6% of the total and the escape of thermal ions for the remaining. We show that these two mechanisms cannot explain the escape of the atmosphere since the magnetic field vanished and even contribute only marginally to this loss. We show that with these two mechanisms, the atmosphere of a Mars analog planet would empty in another giga years and a half. At Venus orbit, the contribution of the dications in the escape rate is negligible. When simulating the hot Jupiter HD 209458 b, the two processes cannot explain the measured escape flux of C+. This study shows that the dications may constitute a source of the escape of planetary atmospheres which had not been taken into account until now. This source, although marginal, is not negligible. The influence of the photoionization is of course large, but cannot explain alone the loss of Mars’ atmosphere nor the atmospheric escape of HD 209458 b.
Published: 2013
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40. Reply to comment by Pätzold et al. on 'Mars Express radio-occultation data: A novel analysis approach'

Author: P.-L. Blelly, Olivier Witasse, Aurélie Marchaudon, Maxime Grandin, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars Exploration Program, 01 natural sciences, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Astrobiology, Atmosphere, Geophysics, Space and Planetary Science, 0103 physical sciences, Mars express, Radio occultation, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; We reply to the Comment by Pätzold et al. on our paper presenting a new analysis approach for Mars Express radio-occultation data. We address each of the main comments, showing that none of them invalidates the method itself, but rather, they underline aspects which could be considered to improve the model. One major issue raised by the Comment is the computation of the frequency residual values, as our model did not take into account the change in frequency between the uplink and the downlink. This problem has been given full consideration, and the corresponding part of the model has been corrected accordingly. The dayside profile analyzed in the original article has been reanalyzed with the updated version of the model, and the results are presented, which show overall improvements. This article is a reply to Pätzold et al.
Published: 2016
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41. Planetary Radio Interferometry and Doppler Experiment (PRIDE) technique: A test case of the Mars Express Phobos fly-by

Author: A. G. Mikhailov, Gerhard Kronschnabl, Jamie McCallum, Tim Natush, Stuart Weston, Wenjun Yang, Weihua Wang, Tatiana Bocanegra Bahamon, Jean-Charles Marty, Pablo de Vicente, Marisa Nickola, Jonathan Quick, Sergei Gulyaev, Rüdiger Haas, Mark Kettenis, J. Kallunki, M. A. Kharinov, A. V. Ipatov, Valery Lainey, Alexander Neidhardt, Guifré Molera Calvés, Dmitry A. Duev, Pascal Rosenblatt, Christian Plötz, Jamie Stevens, Longfei Hao, Giuseppe Cimo, J. W. Kania, Leonid Gurvits, Sergei Pogrebenko, Valeriu Tudose, Andrea Orlati, Michael Lindqvist, James E. J. Lovell, Olivier Witasse, Bo Xia, Joint Institute for VLBI in Europe (JIVE ERIC), Institute of Space Science [Bucharest-Măgurele] (ISS), Royal Observatory of Belgium [Brussels] (ROB), Groupement de Recherche en Géodésie Spatiale (GRGS), Centre National d'Études Spatiales [Toulouse] (CNES), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Earth and Space Sciences [Göteborg], Chalmers University of Technology [Göteborg], Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Institute for Applied Geophysics, the Russian Academy of Sciences [Moscow, Russia] (RAS), School of Civil Engineering and National Centre for Groundwater Research and Training, University of Queensland [Brisbane], Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Land Survey of Finland, and Maanmittauslaitos
Subjects: Time delay and integration, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, symbols.namesake, Planet, 0103 physical sciences, Very-long-baseline interferometry, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing, [PHYS]Physics [physics], Physics, Martian, Spacecraft, business.industry, Astronomy and Astrophysics, Interferometry, Space and Planetary Science, Physics::Space Physics, symbols, Satellite, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics, business, Doppler effect
Abstract: The closest ever fly-by of the Martian moon Phobos, performed by the European Space Agency's Mars Express spacecraft, gives a unique opportunity to sharpen and test the Planetary Radio Interferometry and Doppler Experiments (PRIDE) technique in the interest of studying planet - satellite systems. The aim of this work is to demonstrate a technique of providing high precision positional and Doppler measurements of planetary spacecraft using the Mars Express spacecraft. The technique will be used in the framework of Planetary Radio Interferometry and Doppler Experiments in various planetary missions, in particular in fly-by mode. We advanced a novel approach to spacecraft data processing using the techniques of Doppler and phase-referenced very long baseline interferometry spacecraft tracking. We achieved, on average, mHz precision (30 {\mu}m/s at a 10 seconds integration time) for radial three-way Doppler estimates and sub-nanoradian precision for lateral position measurements, which in a linear measure (at a distance of 1.4 AU) corresponds to ~50 m., Comment: 9 pages, 14 figures. Astronomy and Astrophysics, accepted on 2016/05/31
Published: 2016
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42. Reconceiling the orbital and physical properties of the martian moons

Author: B. Brugger, Olivier Witasse, Thomas Ronnet, Pierre Vernazza, Bertrand Devouard, O. Mousis, Fabrice Cipriani, Pierre Beck, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Solar System, 010504 meteorology & atmospheric sciences, Spectral properties, FOS: Physical sciences, Astronomy and Astrophysics, Mars Exploration Program, 01 natural sciences, Mineralogical composition, Accretion (astrophysics), Astrobiology, Moons of Mars, Accretion disc, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; The origin of Phobos and Deimos is still an open question. Currently, none of the three proposed scenarios for their origin (intact capture of two distinct outer solar system small bodies, co-accretion with Mars, and accretion within an impact-generated disk) are. able to reconcile their orbital and physical properties. Here. we investigate the expected mineralogical composition and size of the grains from which the moons once accreted assuming they formed within an impact-generated accretion disk. A comparison of our results with the present-day spectral properties of the moons allows us to conclude that their building blocks cannot originate from a magma phase, thus preventing their formation in the innermost part of the disk. Instead, gas-to-solid condensation of the building blocks in the outer part of an extended gaseous disk is found as a possible formation mechanism as it does allow reproducing both the spectral and physical properties of the moons. Such a scenario may finally reconcile their orbital and physical properties, alleviating the need to invoke an unlikely capture scenario to explain their physical properties.
Published: 2016
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43. Observations of the surface of Titan by the Radar Altimeters on the Huygens Probe

Author: Håkan Svedhem, Nicolas Floury, Ralph D. Lorenz, J.-P. Lebreton, Wlodek Kofman, Alain Herique, Olivier Witasse, Francesca Ferri, R. Trautner, Dirk Plettemeier, Peter Falkner, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), ESA/ESTEC, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Technische Universität Dresden = Dresden University of Technology (TU Dresden), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), and Universita degli Studi di Padova
Subjects: 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, Terrain, 01 natural sciences, Planetary Data System, Space-based radar, law.invention, Radar observations, symbols.namesake, Amplitude, Intermediate frequency, Space and Planetary Science, law, [SDU]Sciences of the Universe [physics], 0103 physical sciences, symbols, Altimeter, Radar, Titan (rocket family), Titan, 010303 astronomy & astrophysics, Instrumentation, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract: International audience; Results from the radar altimeters on board the Huygens probe are reported, noting the content of data archived on the NASA Planetary Data System and its ESA counterpart. These instruments provide unique high-resolution information on the topography and electrical properties of the Titan surface over a ∼15 km track across a boundary between a bright highland and the dark dissected alluvial terrain on which the probe landed. The highland appears ∼100 m higher than the dark terrain. The dark terrain has a fairly high nadir radar backscatter, consistent with terrestrial lakebeds and alluvial surfaces, and shows small (5–10 m) elevation fluctuations. Possible signatures of surface or volume scattering in the backscatter amplitude and intermediate frequency spectrum are discussed. A previously-undocumented characteristic of the Automatic Gain Control (AGC) on the flight altimeter is noted.
Published: 2016
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44. Plasma observations during the Mars atmospheric 'plume' event of March-April 2012

Author: Stas Barabash, M. Lester, Robin Ramstad, Michael J. Way, David Morgan, Mats Holmström, B. E. S. Hall, Hermann Opgenoorth, David Andrews, Niklas J. T. Edberg, Beatriz Sánchez-Cano, Olivier Witasse, and Donald A. Gurnett
Subjects: Martian, Brightness, 010504 meteorology & atmospheric sciences, Terminator (solar), FOS: Physical sciences, Mars Exploration Program, Atmospheric sciences, 01 natural sciences, Space Physics (physics.space-ph), Article, Plume, Solar wind, Geophysics, Altitude, Physics - Space Physics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Ionosphere, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: We present initial analysis and conclusions from plasma observations made during the reported "Mars plume event" of March - April 2012. During this period, multiple independent amateur observers detected a localized, high-altitude "plume" over the Martian dawn terminator [Sanchez-Lavega et al., Nature, 2015, doi:10.1038/nature14162], the cause of which remains to be explained. The estimated brightness of the plume exceeds that expected for auroral emissions, and its projected altitude greatly exceeds that at which clouds are expected to form. We report on in-situ measurements of ionospheric plasma density and solar wind parameters throughout this interval made by Mars Express, obtained over the same surface region, but at the opposing terminator. Measurements in the ionosphere at the corresponding location frequently show a disturbed structure, though this is not atypical for such regions with intense crustal magnetic fields. We tentatively conclude that the formation and/or transport of this plume to the altitudes where it was observed could be due in part to the result of a large interplanetary coronal mass ejection (ICME) encountering the Martian system. Interestingly, we note that the only similar plume detection in May 1997 may also have been associated with a large ICME impact at Mars., 21 pages, 6 figures, article accepted for publication in J. Geophys. Res
Published: 2016

45. First detection of the O III 495.8911 and 500.6843 nm lines in the Earth's upper atmosphere

Author: Roland Thissen, Tom G. Slanger, Olivier Witasse, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Doubly ionized oxygen, Astrophysics::Cosmology and Extragalactic Astrophysics, medicine.disease_cause, 01 natural sciences, Ion, Atmosphere, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), medicine, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, lcsh:Science, 010303 astronomy & astrophysics, Spectrograph, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Very Large Telescope, lcsh:QC801-809, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Geology, Astronomy and Astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Ultraviolet, lcsh:Physics
Abstract: We report the first detection of two emission lines of the atomic oxygen doubly-charged ion at 495.8911 and 500.6843 nm in the terrestrial upper atmosphere. They correspond to the transitions 1D2-3P1 and 1D2-3P2 of the O++ ion, respectively. The measurements were performed on 30 October 2003 during the "Halloween" storms, with the Ultraviolet and Visual Echelle Spectrograph (UVES) mounted on the Very Large Telescope (VLT) in Chile. The intensities of these emissions are ~70 mRayleigh, and ~260 mRayleigh, respectively. These emissions constitute a new diagnostic of the state of the ionosphere.
Published: 2011
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46. Methane on Mars: Current observations, interpretation, and future plans

Author: Sushil K. Atreya, Richard W. Zurek, François Forget, Olivier Witasse, P. Buford Price, Paul R. Mahaffy, Christopher R. Webster, and Vincent Chevrier
Subjects: Martian, 010504 meteorology & atmospheric sciences, Meteorology, Space and Planetary Science, Interpretation (philosophy), 0103 physical sciences, Library science, Astronomy and Astrophysics, Mars Exploration Program, 010303 astronomy & astrophysics, 01 natural sciences, Geology, 0105 earth and related environmental sciences
Abstract: An ESA-ASI organized workshop on the Martian methane brought together nearly one hundred enthusiastic participants to ESRIN, Frascati, Italy from world over – two thirds from Europe, one-fifth from the US, and the rest from other places. The program comprised thirteen hours of oral presentations, two hours of posters, and, most noteworthy, about five hours of discussions, over a three-day period from November 25th through the 27th, 2009. The topics cast a wide net, ranging from earth-based and space observations to their implications for potential geology and biology, from models and supporting laboratory measurements to future exploration of Mars. This is a synopsis of the main themes covered at the Workshop, many of which are discussed in detail in peerreviewed papers in this special issue.
Published: 2011
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47. Lander radioscience for obtaining the rotation and orientation of Mars

Author: Stefaan Burger, Attilio Rivoldini, Olivier Witasse, Tilman Spohn, Sami W. Asmar, Bernd Häusler, Gerald Schubert, Georges Balmino, Sébastien Le Maistre, Frank Budnik, Pascal Rosenblatt, Michel Menvielle, Olivier de Viron, William M. Folkner, Véronique Dehant, Jean-Pierre Barriot, Philippe Lognonné, Marie Yseboodt, Paolo Tortora, Daniel Orban, Jens Biele, Etienne Renotte, Özgür Karatekin, Martin Pätzold, Tim Van Hoolst, Michel Mitrovic, Richard Biancale, Jeremy Benoist, Royal Observatory of Belgium [Brussels] (ROB), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Centre Spatial de Liège (CSL), Université de Liège, Services communs OMP (UMS 831), 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), Centre National d'Études Spatiales [Toulouse] (CNES), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln, European Space Agency (ESA), V. Dehant, W. Folkner, E. Renotte, D. Orban, S. Asmar, G. Balmino, J-P Barriot, J. Benoist, R. Biancale, J. Biele, F. Budnik, S. Burger, O. de Viron, B. Häusler, Ö. Karatekin, S. Le Maistre, P. Lognonné, M. Menvielle, M. Mitrovic, M. Pätzold, A. Rivoldini, P. Rosenblatt, G. Schubert, T. Spohn, P. Tortora, T. Van Hoolst, O. Witasse, and M. Yseboodt
Subjects: Angular momentum, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Physics::Geophysics, Planet, Martian surface, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Nutation, Chandler wobble, X-band signal, Astronomy and Astrophysics, Geophysics, Mars Exploration Program, Radioscience, Moment of inertia, Mars length-of-day, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Timekeeping on Mars, Astrophysics::Earth and Planetary Astrophysics, Mars nutation
Abstract: The paper presents the concept, the objectives, the approach used, and the expected performances and accuracies of a radioscience experiment based on a radio link between the Earth and the surface of Mars. This experiment involves radioscience equipment installed on a lander at the surface of Mars. The experiment with the generic name lander radioscience (LaRa) consists of an X-band transponder that has been designed to obtain, over at least one Martian year, two-way Doppler measurements from the radio link between the ExoMars lander and the Earth (ExoMars is an ESA mission to Mars due to launch in 2013). These Doppler measurements will be used to obtain Mars’ orientation in space and rotation (precession and nutations, and length-of-day variations). More specifically, the relative position of the lander on the surface of Mars with respect to the Earth ground stations allows reconstructing Mars’ time varying orientation and rotation in space. Precession will be determined with an accuracy better by a factor of 4 (better than the 0.1% level) with respect to the present-day accuracy after only a few months at the Martian surface. This precession determination will, in turn, improve the determination of the moment of inertia of the whole planet (mantle plus core) and the radius of the core: for a specific interior composition or even for a range of possible compositions, the core radius is expected to be determined with a precision decreasing to a few tens of kilometers. A fairly precise measurement of variations in the orientation of Mars’ spin axis will enable, in addition to the determination of the moment of inertia of the core, an even better determination of the size of the core via the core resonance in the nutation amplitudes. When the core is liquid, the free core nutation (FCN) resonance induces a change in the nutation amplitudes, with respect to their values for a solid planet, at the percent level in the large semi-annual prograde nutation amplitude and even more (a few percent, a few tens of percent or more, depending on the FCN period) for the retrograde ter-annual nutation amplitude. The resonance amplification depends on the size, moment of inertia, and flattening of the core. For a large core, the amplification can be very large, ensuring the detection of the FCN, and determination of the core moment of inertia. The measurement of variations in Mars’ rotation also determines variations of the angular momentum due to seasonal mass transfer between the atmosphere and ice caps. Observations even for a short period of 180 days at the surface of Mars will decrease the uncertainty by a factor of two with respect to the present knowledge of these quantities (at the 10% level). The ultimate objectives of the proposed experiment are to obtain information on Mars’ interior and on the sublimation/condensation of CO2 in Mars’ atmosphere. Improved knowledge of the interior will help us to better understand the formation and evolution of Mars. Improved knowledge of the CO2 sublimation/condensation cycle will enable better understanding of the circulation and dynamics of Mars’ atmosphere.
Published: 2009
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48. Venus Express: Scientific goals, instrumentation, and scenario of the mission

Author: A. Acomazzo, Pierre Drossart, A. Clochet, D. Neveance, J. Rodrigues-Cannabal, Oleg Korablev, T. Zhang, Stas Barabash, M. Warhaut, Håkan Svedhem, J. Fabrega, M. Coradini, Giuseppe Piccioni, D. McCoy, J. L. Bertaux, M. Petzold, Detlef Koschny, Vittorio Formisano, D. V. Titov, W. J. Markiewicz, Olivier Witasse, Bernd Haeusler, Jean-Pierre Lebreton, E. Lellouch, T. Schirmann, Fredric W. Taylor, Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Swedish Institute of Space Physics [Kiruna] (IRF), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire 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), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Universität der Bundeswehr München [Neubiberg], Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Institut für Geophysik und Meteorologie [Köln], Universität zu Köln, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), University of Oxford [Oxford], European Space Operations Center (ESOC), EADS Astrium SAS, Agence Spatiale Européenne (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität zu Köln = University of Cologne, and University of Oxford
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Engineering, 010504 meteorology & atmospheric sciences, Spacecraft, biology, business.industry, Payload, Aerospace Engineering, Astronomy and Astrophysics, Venus, biology.organism_classification, 01 natural sciences, 7. Clean energy, Astrobiology, Depth sounding, Broad spectrum, Space and Planetary Science, Planet, 0103 physical sciences, Mars express, Instrumentation (computer programming), business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The first European mission to Venus (Venus Express) is described. It is based on a repeated use of the Mars Express design with minor modifications dictated in the main by more severe thermal environment at Venus. The main scientific task of the mission is global exploration of the Venusian atmosphere, circumplanetary plasma, and the planet surface from an orbiting spacecraft. The Venus Express payload includes seven instruments, five of which are inherited from the missions Mars Express and Rosetta. Two instruments were specially designed for Venus Express. The advantages of Venus Express in comparison with previous missions are in using advanced instrumentation and methods of remote sounding, as well as a spacecraft with a broad spectrum of capabilities of orbital observations. © Pleiades Publishing, Inc., 2006.
Published: 2006
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49. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

Author: Olivier Witasse, Konrad Schwingenschuh, Bobby Kazeminejad, Andrew J. Ball, Georg Fischer, Helmut Lammer, Athena Coustenis, Helmut O. Rucker, EGU, Publication, Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), and European Space Agency (ESA)-European Space Agency (ESA)
Subjects: Atmospheric Science, Hypersonic speed, Haze, 010504 meteorology & atmospheric sciences, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Atmospheric model, Atmospheric sciences, 01 natural sciences, symbols.namesake, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Aerodynamic drag, Extreme value theory, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, Computational physics, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, symbols, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family), lcsh:Physics
Abstract: Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004) (Icarus, Vol. 170, 91-112) engineering model and derive extreme case (i.e. minimum and maximum profiles) temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997) (ESA SP-1177) profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.
Published: 2005

50. Mars Express radio‐occultation data: A novel analysis approach

Author: Maxime Grandin, Olivier Witasse, Aurélie Marchaudon, P.-L. Blelly, University of Oulu, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Spacecraft, Computer science, business.industry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars Exploration Program, Geophysics, Inverse problem, 01 natural sciences, Occultation, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Radio occultation, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Radio wave, Radio Science
Abstract: International audience; The Mars Express Radio Science (MaRS) experiment on board Mars Express has been providing radio-occultation data since early 2004. The analysis method currently used to retrieve neutral atmosphere and ionosphere profiles is based on the resolution of a complex inverse problem. The solution to such a problem is obtained under strong assumptions on the atmosphere and the ionosphere and with some limitations. Here we developed a novel method for radio-occultation data analysis based on a direct approach which overcomes some of the difficulties related to the standard inversion. This new method is based on a numerical model of the atmosphere and the ionosphere of Mars computing the propagation of the radio waves from the spacecraft to the receiver on Earth. The main interest of such an approach lies in the intrinsic and coherent coupling between the neutral part and the ionized part of the planetary environment, which gives physical constrains on the retrieved profiles. We have applied this new method to radio occultation experiments performed by MaRS, and we present the results obtained in two different occultation configurations. We discuss the differences which emerge from the standard analysis and the gain that such a method can give to the analysis of planetary environments.
Published: 2014
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