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13 results on '"Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt"'

1. Photometric changes on Saturn's Titan: Evidence for active cryovolcanism

Author

Dale P. Cruikshank, Angioletta Coradini, F. Leader, Pierre Drossart, Karl L. Mitchell, P. Cerroni, Robert M. Nelson, Randolph L. Kirk, Dennis L. Matson, Stephen D. Wall, Fabrizio Capaccioni, John C. Pearl, Kevin H. Baines, Vito Mennella, M. Combes, P. D. Nicholson, Gianrico Filacchione, M. D. Boryta, Ralf Jaumann, L. W. Kamp, Yves Langevin, Rosaly M. C. Lopes, Bruno Sicardy, Thomas B. McCord, Jonathan I. Lunine, Vittorio Formisano, Jean-Pierre Bibring, Roger N. Clark, Bruce Hapke, Patrick G. J. Irwin, Christophe Sotin, Giancarlo Bellucci, William D. Smythe, Jet Propulsion Laboratory, California Institute of Technology (JPL), US Geological Survey, Flagstaff, Department of Geology and Planetary Science, University of Pittsburgh, Department of Earth Science and Astronomy, Mt. San Antonio College, Walnut, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, United States Geological Survey, Denver, SETI Institute, NASA Ames Research Center, Moffett Field, 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ISFI, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Bear Fight Center, Space Science Institute, Winthrop, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Department of Astronomy, Cornell University, Clarendon Laboratory, Department of Physics, University of Oxford, and NASA/Goddard Space Flight Center (NASA/GSFC)

Subjects
Synthetic aperture radar, Spectrometer, Infrared, cryovolcanism, law.invention, Astrobiology, Photometry, Orbiter, symbols.namesake, Geophysics, law, symbols, General Earth and Planetary Sciences, Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Geology, Remote sensing
Abstract

International audience; We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March 18, 2006. We previously reported spectrophotometric variability at another location (26°S, 78°W). Cassini Synthetic Aperture RADAR (SAR) images find that the surface morphology at both locations is consistent with surface flows possibly resulting from cryovolcanic activity (Wall et al., companion paper, this issue). The VIMS-reported time variability and SAR morphology results suggest that Titan currently exhibits intermittent surface changes consistent with present ongoing surface processes. We suggest that these processes involve material from Titan's interior being extruded or effused and deposited on the surface, as might be expected from cryovolcanism.

Published
2016
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2. Comparative studies of meteoroid-planet interaction in the inner solar system

Author

Maxim L. Khodachenko, Detlef Koschny, Jeremie Vaubaillon, Helmut Lammer, Apostolos A. Christou, Valeria Mangano, Bobby Kazeminejad, Jonathan McAuliffe, Christophe Kolb, Juergen Oberst, Helmut O. Rucker, Armagh Observatory, College Hill, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften (IWF), Università degli Studi di Padova = University of Padua (Unipd), Istituto di Fisica dello Spazio Interplanetario (IFSI), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
Meteor (satellite), Solar System, Meteors, Meteoroid, Computer science, Astronomy and Astrophysics, Meteoroids, Atmosphere of Mars, Astrobiology, Planetary science, Space and Planetary Science, Planet, Terrestrial planet, Instrumentation (computer programming), Terrestrial planets, Moon, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We review the current state of studies in planet-meteoroid interactions, a relatively new discipline in planetary science. Recent observations of phenomena such as meteor trails in the atmosphere of Mars and impact flashes on the Moon have prompted new theoretical work in the field. However, our ability to test these new models and advance our understanding of the processes involved is being inhibited by the lack of systematic long-term observations with instruments dedicated to the task. Here we consider the different types of meteoroid effects on a planetary environment. The current state of knowledge leads us to expect signatures detectable by existing instrumentation, either serendipitously or, in a more targeted fashion, by employing such apparatus in innovative ways and making use of already available model predictions. These will result in near-term advances in the field, to be used towards incorporating meteoroid-effect-detecting capabilities explicitly into future planetary instrumentation or building dedicated instruments.

Published
2007
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3. Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

Author

Robert M. Nelson, Kevin H. Baines, Ralf Jaumann, Angioletta Coradini, Christophe Sotin, Bruno Sicardy, Fabrizio Capaccioni, Mark R. Showalter, Dale P. Cruikshank, Caitlin A. Griffith, Pierre Drossart, Robert H. Brown, B. J. Buratti, Yves Langevin, Dennis L. Matson, Vito Mennella, Charles A. Hibbitts, Roger N. Clark, Priscilla Cerroni, Vittorio Formisano, Giancarlo Bellucci, P. D. Nicholson, Gary B. Hansen, N. Baugh, Tom Momary, Thomas B. McCord, 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), Department of Planetary Sciences, and Lunar and Planetary Laboratory, University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Consiglio Nazionale delle Ricerche, Isituto di Fisica dello Spazio Interplanetario, Via Fosso del Cavaliere, Consiglio Nazionale delle Ricerche, Isituto di Astrofisica Spaziale, via Fosso del Cavaliere, US Geological Survey, Denver, SETI Institute, NASA Ames Research Center, Moffett Field, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Earth and Space Sciences, University of Washington, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University

Subjects
Solar System, 010504 meteorology & atmospheric sciences, Infrared, Rings of Saturn, Astrophysics, 01 natural sciences, symbols.namesake, Impact crater, 0103 physical sciences, VIMS, Atmosphere of Titan, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Spectrometer, Astronomy, Astronomy and Astrophysics, solar system, Satellites de Glace, Saturn, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Absorption band, infrared, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family)
Abstract

International audience; The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO{2}, and ferrous iron. Iapetus contains CO{2} and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be CO{2} and CH{3}D. As determined from cloud motions, the winds at altitude 25-30 km in the south polar region of Titan appear to be moving in a prograde direction at velocity ˜ 1 m s-1. Circular albedo features on Titan's surface, seen at 2.02 mu m, may be palimpsests remaining from the rheological adjustment of ancient impact craters. As such, their long-term persistence is of special interest in view of the expected precipitation of liquids and solids from the atmosphere. Saturn's rings have changed little in their radial structure since the Voyager flybys in the early 1980s. Spectral absorption bands tentatively attributed to Fe2+ suggest that iron-bearing silicates are a source of contamination of the C ring and the Cassini Division.

Published
2006
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4. A Martian PFS average spectrum: Comparison with ISO SWS

Author

M. Rataj, Marco Giuranna, A. Maturilli, Igor Khatuntsev, V. I. Moroz, Davide Grassi, Emmanuel Lellouch, Sergio Fonti, Giuseppe Piccioni, Bortolino Saggin, H. Hirsh, L. V. Zasova, Piotr Orleanski, Nikolay Ignatiev, Vittorio Formisano, T. Encrenaz, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Dipartimento di Fisica, Università di Lecce, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Space Research Center, Polish Academy of Sciences (Warsaw), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), and Politecnico di Milano [Milan] (POLIMI)

Subjects
Physics, Martian, business.industry, Planetary Fourier Spectrometer, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, Astrophysics, Optics, Space and Planetary Science, Planet, Radiance, Astrophysics::Earth and Planetary Astrophysics, Monochromatic color, Spectral resolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business
Abstract

International audience; The evaluation of the planetary Fourier spectrometer performance at Mars is presented by comparing an average spectrum with the ISO spectrum published by Lellouch et al. [2000. Planet. Space Sci. 48, 1393.]. First, the average conditions of Mars atmosphere are compared, then the mixing ratios of the major gases are evaluated. Major and minor bands of CO 2 are compared, from the point of view of features characteristics and bands depth. The spectral resolution is also compared using several solar lines. The result indicates that PFS radiance is valid to better than 1% in the wavenumber range 1800-4200 cm -1 for the average spectrum considered (1680 measurements). The PFS monochromatic transfer function generates an overshooting on the left-hand side of strong narrow lines (solar or atmospheric). The spectral resolution of PFS is of the order of 1.3 cm -1 or better. A large number of narrow features to be identified are discovered.

Published
2005
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5. Diurnal tidal stresses on Titan

Author

Sohl, Frank, Solomonidou, Anezina, Wagner, Frank W., Coustenis, Athéna, Hussmann, Hauke, Schulze-Makuch, Dirk, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), and Deutsches Zentrum für Luft- und Raumfahrt (DLR)

Subjects
internal ocean, composition, tides, cryovolcanism, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan, Cassini-Huygens, interior structure
Abstract

International audience; Interior models and amplitude patterns of diurnal tidal stresses on Titan are calculated. The structural models are required to satisfy the satellite's mean density, polar moment-of-inertia factor MoI, and tidal potential Love number k2 as derived from Cassini gravity field data. The tidal stress pattern is found to correspond to the locations of cryovolcanic candidate areas on Titan's leading hemisphere. A relatively warm, low-ammonia water ocean could further increase Titan's habitable potential.

Published
2013

6. Evolution of icy satellites

Author

William B. McKinnon, Diego Turrini, Frank Sohl, T. Van Hoolst, Christophe Sotin, Valéry Lainey, Gerald Schubert, Gabriel Tobie, H. Hussmann, Dennis L. Matson, Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics (IGPP/UCLA), Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Jet Propulsion Laboratory, California Institute of Technology (JPL), Department of Earth and Planetary Sciences, Washington University, Washington University in Saint Louis (WUSTL), Université de Nantes (UN), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Observatoire Royal de Belgique (ORB), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Rhea, Iapetus, Dwarf planet, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Tidal heating, Io, 01 natural sciences, Astrobiology, symbols.namesake, Enceladus, Neptune, 0103 physical sciences, evolution, Tethys, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Outer planet moons, Pluto, Dione, Astronomy, Astronomy and Astrophysics, Galilean moons, Phoebe, 13. Climate action, Space and Planetary Science, Physics::Space Physics, symbols, Natural satellite, icy satellites, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Europa, Titan, Geology
Abstract

International audience; Evolutionary scenarios for the major satellites of Jupiter, Saturn, Neptune, and Pluto-Charon are discussed. In the Jovian system the challenge is to understand how the present Laplace resonance of Io, Europa, and Ganymede was established and to determine whether the heat being radiated by Io is in balance with the present tidal dissipation in the moon. In the Saturnian system, Enceladus and Titan are the centers of attention. Tidal heating is the likely source of activity at the south pole of Enceladus, although the details of how the heating occurs are not understood. An evolutionary scenario based on accretion and internal differentiation is presented for Titan, whose present substantial orbital eccentricity is not associated with any dynamical resonance. The source and maintenance of methane in Titan's present atmosphere remain uncertain. Though most attention on the Saturnian moons focuses on Titan and Enceladus, the mid-size satellites Iapetus, Rhea, Tethys, and the irregular satellite Phoebe also draw our interest. An evolutionary scenario for Iapetus is presented in which spin down from an early rapidly rotating state is called upon to explain the satellite's present oblate shape. The prominent equatorial ridge on Iapetus is unexplained by the spin down scenario. A buckling instability provides another possible explanation for the oblateness and equatorial ridge of Iapetus. Rhea is the only medium-size Saturnian satellite for which there are gravity data at present. The interpretation of these data are uncertain, however, since it is not known if Rhea is in hydrostatic equilibrium. Pluto and Charon are representative of the icy dwarf planets of the Kuiper belt. Did they differentiate as they evolved, and do either of them have a subsurface liquid water ocean? New Horizons might provide some answers when it arrives at these bodies.

Published
2010
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7. Chemical Composition of Icy Satellite Surfaces

Author

Athena Coustenis, Dale P. Cruikshank, J. B. Dalton, Katrin Stephan, Angioletta Coradini, Robert W. Carlson, T. B. McCord, Jet Propulsion Laboratory, California Institute of Technology (JPL), SETI Institute, NASA Ames Research Center, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Bear Fight Institute, 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Istituto di Fisica dello Spazio Interplanetario (IFSI), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
Solar System, Planetary surface, Spacecraft, business.industry, Astronomy and Astrophysics, medicine.disease_cause, Physics::Geophysics, Astrobiology, Planetary science, Space and Planetary Science, medicine, Environmental science, Satellite, icy satellites, Astrophysics::Earth and Planetary Astrophysics, Aqueous geochemistry, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Chemical composition, Ultraviolet
Abstract

International audience; Much of our knowledge of planetary surface composition is derived from remote sensing over the ultraviolet through infrared wavelength ranges. Telescopic observations and, in the past few decades, spacecraft mission observations have led to the discovery of many surface materials, from rock-forming minerals to water ice to exotic volatiles and organic compounds. Identifying surface materials and mapping their distributions allows us to constrain interior processes such as cryovolcanism and aqueous geochemistry. The recent progress in understanding of icy satellite surface composition has been aided by the evolving capabilities of spacecraft missions, advances in detector technology, and laboratory studies of candidate surface compounds. Pioneers 10 and 11, Voyagers I and II, Galileo, Cassini and the New Horizons mission have all made significant contributions. Dalton (Space Sci. Rev., 2010, this issue) summarizes the major constituents found or inferred to exist on the surfaces of the icy satellites (cf. Table 1 from Dalton, Space Sci. Rev., 2010, this issue), and the spectral coverage and resolution of many of the spacecraft instruments that have revolutionized our understanding (cf. Table 2 from Dalton, Space Sci. Rev., 2010, this issue). While much has been gained from these missions, telescopic observations also continue to provide important constraints on surface compositions, especially for those bodies that have not yet been visited by spacecraft, such as Kuiper Belt Objects (KBOs), trans-Neptunian Objects (TNOs), Centaurs, the classical planet Pluto and its moon, Charon. In this chapter, we will discuss the major satellites of the outer solar system, the materials believed to make up their surfaces, and the history of some of these discoveries. Formation scenarios and subsequent evolution will be described, with particular attention to the processes that drive surface chemistry and exchange with interiors. Major similarities and differences between the satellites are discussed, with an eye toward elucidating processes operating throughout the outer solar system. Finally we discuss the outermost satellites and other bodies, and summarize knowledge of their composition. Much of this review is likely to change in the near future with ongoing and planned outer planet missions, adding to the sense of excitement and discovery associated with our exploration of our planetary neighborhood.

Published
2010
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8. Saturn's icy satellites investigated by Cassini-VIMS. I. Full-disk properties: 350 5100 nm reflectance spectra and phase curves

Author

Filacchione, Gianrico, Capaccioni, Fabrizio, Mccord, Thomas B., Coradini, Angioletta, Cerroni, Priscilla, Bellucci, Giancarlo, Tosi, Federico, d'Aversa, E., Formisano, Vittorio, Brown, Robert H., Baines, Kevin H., Bibring, Jean-Pierre, Buratti, B. J., Clark, Roger N., Combes, Michel, Cruikshank, Dale P., Drossart, Pierre, Jaumann, Ralf, Langevin, Yves, Matson, Dennis L., Mennella, Vito, Nelson, Robert M., Nicholson, Philip D., Sicardy, Bruno, Sotin, Christophe, Hansen, Gary B., Hibbitts, K., Showalter, Mark R., Newman, S., Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Bear Fight Center, Space Science Institute, Winthrop, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona (LPL), Jet Propulsion Laboratory, California Institute of Technology (JPL), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), United States Geological Survey, Denver, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), NASA Ames Research Center, Astrophysics Branch, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Department of Astronomy, Cornell University, 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), Department of Earth and Space Sciences, University of Washington, and Department of Electrical Engineering, Stanford University

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Saturn's icy satellites are among the main scientific objectives of the Cassini-VIMS (Visual and Infrared Mapping Spectrometer) experiment. This paper contains a first systematic and comparative analysis of the full-disk spectral properties of Dione, Enceladus, Epimetheus, Hyperion, Iapetus, Mimas, Phoebe, Rhea and Tethys as observed by VIMS from July 2004 to June 2005. The disk integrated properties (350-5100 nm reflectance spectra and phase curves at 550-2232 nm) and images of satellites are reported and discussed in detail together with the observed geometry. In general, the spectra in the visible spectral range are almost featureless and can be classified according to the spectral slopes: from the bluish Enceladus and Phoebe to the redder Iapetus, Hyperion and Epimetheus. In the 1000-1300 nm range the spectra of Enceladus, Tethys, Mimas and Rhea are characterized by a negative slope, consistent with a surface largely dominated by water ice, while the spectra of Iapetus, Hyperion and Phoebe show a considerable reddening pointing out the relevant role played by darkening materials present on the surface. In between these two classes are Dione and Epimetheus, which have a flat spectrum in this range. The main absorption bands identified in the infrared are the 1520, 2020, 3000 nm H 2O/OH bands (for all satellites), although Iapetus dark terrains show mostly a deep 3000 nm band while the 1520 and 2020 nm bands are very faint. In this spectral range, the Iapetus spectrum is characterized by a strong reddening. The CO 2 band at 4260 nm and the Fresnel ice peak around 3100 nm are evident only on Hyperion, Phoebe and Iapetus. The phase curves at 550 and at 2232 nm are reported for all the available observations in the 0°-144° range; Rhea shows an opposition surge at visible wavelengths in the 0.5°-1.17° interval. The improvement on the retrieval of the full-disk reflectance spectra can be appreciated by a direct comparison with ground-based telescopic data available from literature. Finally, data processing strategies and recent upgrades introduced in the VIMS-V calibration pipeline (flat-field and destriping-despiking algorithm) are discussed in appendices.

Published
2007
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9. The evolution of Titan's mid-latitude clouds

Author

Vito Mennella, B. J. Buratti, Jason W. Barnes, Yves Langevin, Roger N. Clark, Paulo Penteado, Dale P. Cruikshank, Ralf Jaumann, Robert M. Nelson, Robert H. Brown, L. A. Soderblom, Giancarlo Bellucci, J. P. Bibring, M. Combes, Christophe Sotin, Fabrizio Capaccioni, R. Kursinski, Priscilla Cerroni, T. B. McCord, Vittorio Formisano, Pierre Drossart, Bruno Sicardy, Angioletta Coradini, P. D. Nicholson, Caitlin A. Griffith, Kevin H. Baines, Douglas M. Matson, 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), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), US Geological Survey, Flagstaff, SETI Institute, NASA Ames Research Center, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Department of Earth and Space Sciences, University of Washington, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), and Department of Astronomy, Cornell University

Subjects
010504 meteorology & atmospheric sciences, Meteorology, Extraterrestrial Environment, Infrared, clouds, Atmospheric sciences, 01 natural sciences, Troposphere, symbols.namesake, 0103 physical sciences, VIMS, Spacecraft, 010303 astronomy & astrophysics, Optical depth, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, Spectrometer, Atmosphere, Spectrum Analysis, Satellites de Glace, Saturn, 13. Climate action, Middle latitudes, symbols, Cassini, Titan, Titan (rocket family), Longitude, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Methane, Geology
Abstract

International audience; Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal that the horizontal structure, height, and optical depth of Titan's clouds are highly dynamic. Vigorous cloud centers are seen to rise from the middle to the upper troposphere within 30 minutes and dissipate within the next hour. Their development indicates that Titan's clouds evolve convectively; dissipate through rain; and, over the next several hours, waft downwind to achieve their great longitude extents. These and other characteristics suggest that temperate clouds originate from circulation-induced convergence, in addition to a forcing at the surface associated with Saturn's tides, geology, and/or surface composition.

Published
2005
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10. A 5-Micron-Bright Spot on Titan: Evidence for Surface Diversity

Author

Roger N. Clark, Michael E. Brown, Dale P. Cruikshank, Emily L. Schaller, Jason Perry, Angioletta Coradini, Thomas B. McCord, Alfred S. McEwen, Jason W. Barnes, Elizabeth P. Turtle, Bonnie J. Buratti, Robert H. Brown, Michael Janssen, Yves Langevin, J. Barbara, Henry G. Roe, P. D. Nicholson, Giancarlo Bellucci, Caitlin A. Griffith, Ralf Jaumann, Jean-Pierre Bibring, S. Fussner, Richard West, Christophe Sotin, Vittorio Formisano, Dennis L. Matson, Bruno Sicardy, M. Combes, Kevin H. Baines, Ralph D. Lorenz, Charles Elachi, Pierre Drossart, Fabrizio Capaccioni, A. H. Bouchez, Priscilla Cerroni, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Jet Propulsion Laboratory, California Institute of Technology (JPL), Geological and Planetary Sciences, California Institute of Technology, Pasadena, 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), US Geological Survey, Flagstaff, NASA Goddard Institute for Space Studies, Columbia University, W. M. Keck Observatory, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), SETI Institute, NASA Ames Research Center, Moffett Field, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Department of Earth and Space Sciences, University of Washington, and Department of Astronomy, Cornell University

Subjects
Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Infrared, 01 natural sciences, Albedo feature, symbols.namesake, Optics, Dry Ice, 0103 physical sciences, VIMS, Geophysical Phenomena, Imaging science, Spacecraft, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, Spectrometer, Atmosphere, business.industry, Spectrum Analysis, Ice, Temperature, Water, Astronomy, Wavelength, Satellites de Glace, Saturn, Bright spot, infrared, symbols, Cassini, Titan, business, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Methane, Geology
Abstract

International audience; Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80°W and 20°S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena.

Published
2005
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11. The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission

Author

Formisano, V., Angrilli, F., Arnold, G., Atreya, S., Bianchini, G., Biondi, D., Blanco, A., Blecka, M. I., Coradini, A., Colangeli, L., Ekonomov, A., Esposito, F., Fonti, S., Giuranna, M., Grassi, D., Gnedykh, V., Grigoriev, A., Hansen, G., Hirsh, H., Khatuntsev, I., Kiselev, A., Ignatiev, N., Jurewicz, A., Lellouch, E., Moreno, J. L., Marten, A., Mattana, A., Maturilli, A., Mencarelli, E., Michalska, M., Moroz, V., Moshkin, B., Nespoli, F., Nikolsky, Y., Orfei, R., Orleanski, P., Orofino, V., Palomba, E., Patsaev, D., Piccioni, G., Rataj, M., Rodrigo, R., Rodriguez, J., Rossi, M., bortolino saggin, Titov, D., Zasova, L., Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Dipartimento di Fisica, Università di Lecce, Space Research Center, Polish Academy of Sciences (Warsaw), INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Institute of Space Research, Russian Academy of Science (IKI/RAN), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), Planetary Science Institute, Pacific Northwest Division, Department of Earth and Space Science, seattle, Instituto de Astrofisica de Andalucia, CSIC (IAA), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), and Politecnico di Milano [Milan] (POLIMI)

Subjects
Space and Planetary Science, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The Planetary Fourier Spectrometer (PFS) for the Mars Express mission is an infrared spectrometer optimised for atmospheric studies. This instrument has a short wave (SW) channel that covers the spectral range from 1700 to 8200.0cm-1 (1.2- 5.5mum) and a long-wave (LW) channel that covers 250- 1700cm-1 (5.5- 45mum). Both channels have a uniform spectral resolution of 1.3cm-1. The instrument field of view FOV is about 1.6o (FWHM) for the Short Wavelength channel (SW) and 2.8o (FWHM) for the Long Wavelength channel (LW) which corresponds to a spatial resolution of 7 and 12 km when Mars is observed from an height of 250 km. PFS can provide unique data necessary to improve our knowledge not only of the atmosphere properties but also about mineralogical composition of the surface and the surface-atmosphere interaction. The SW channel uses a PbSe detector cooled to 200-220 K while the LW channel is based on a pyroelectric ( LiTaO3) detector working at room temperature. The intensity of the interferogram is measured every 150 nm of physical mirrors displacement, corresponding to 600 nm optical path difference, by using a laser diode monochromatic light interferogram (a sine wave), whose zero crossings control the double pendulum motion. PFS works primarily around the pericentre of the orbit, only occasionally observing Mars from large distances. Each measurements take 4 s, with a repetition time of 8.5 s. By working roughly 0.6 h around pericentre, a total of 330 measurements per orbit will be acquired 270 looking at Mars and 60 for calibrations. PFS is able to take measurements at all local times, facilitating the retrieval of surface temperatures and atmospheric vertical temperature profiles on both the day and the night side.

Published
2005
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12. Water clouds and dust aerosols observations with PFS MEX at Mars

Author

Sergio Fonti, M. I. Blecka, A. Maturilli, H. Hirsch, M. Rataj, Bortolino Saggin, D. Patsaev, Marco Giuranna, L. V. Zasova, Nikolay Ignatiev, Giuseppe Piccioni, Emmanuel Lellouch, Davide Grassi, Anatoly I. Grigoriev, Igor Khatuntsev, V. I. Moroz, Vittorio Formisano, B. E. Moshkin, A. Mattana, A. P. Ekonomov, Gary B. Hansen, Institute of Space Research, Russian Academy of Science (IKI/RAN), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité)-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 Paris Cité (UPCité), University of Washington [Seattle], Space Research Center, Polish Academy of Sciences (Warsaw), Dipartimento di Fisica, Università di Lecce, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), and Politecnico di Milano [Milan] (POLIMI)

Subjects
Effective radius, Ice cloud, geography, geography.geographical_feature_category, Opacity, Astronomy and Astrophysics, Scale height, Mars Exploration Program, Noon, Atmospheric sciences, Volcano, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Tharsis
Abstract

International audience; Observations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrared (long-wavelength channel of PFS) in a self-consistent way using the same spectrum. Orographic ice clouds are identified above Olympus (orbit 37) and Ascraeus Mons (orbit 68). Both volcanoes were observed near noon at Ls=337° and 342°, respectively. The effective radius of ice particles is preliminary estimated as 1-3 mum, changing along the flanks. The corresponding visual opacity changes in the interval 0.2-0.4 above Olympus and 0.1-0.6 above Ascraeus Mons. In the case of Ascraeus Mons, the ice clouds were observed mainly above the Southern flank of the volcano with maximum opacity near the summit. In the case of Olympus, the clouds were found above both sides of the top. A different type of ice cloud is observed at latitudes above 50°N (orbit 68) in the polar hood: the effective particle radius is estimated to be 4 mum. Below the 1 mb level an inversion in the temperature profiles is found with maximum temperature at around 0.6 mb. Along orbit 68 it appears above Alba Patera, then it increases to the north and decreases above the CO 2 polar cap. Beginning from latitude 20°S above Tharsis (orbit 68), the ice clouds and dust contribute equally to the spectral shape. Further on, the ice clouds are found everywhere along orbit 68 up to the Northern polar cap, except the areas between the Northern flank of Ascraeus Mons (below 10 km) and the edge of Alba Patera. Orbit 41 is shifted from the orbit 68 by roughly 180° longitude and passes through Hellas. Ice clouds are not visible in this orbit at latitudes below 80°S. The dust opacity is anticorrelated with the surface altitude. From 70°S to 25°N latitude the vertical dust distribution follows an exponential law with a scale height of 11.5±0.5 km, which corresponds to the gaseous scale height near noon and indicates a well-mixed condition. The 9 mum dust opacity, reduced to zero surface altitude, is found to be 0.25±0.05, which corresponds to a visual opacity of 0.5-0.7 (depending on the particle size).

Published
2005
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13. Optical alteration of complex organics induced by ion-irradiation: 1. Laboratory experiments suggest unusual space weathering trend

Author

L. V. Starukhina, Elisa Distefano, Gabriele Arnold, L. V. Moroz, M. A. Barucci, G. A. Baratta, Elisabetta Dotto, Giovanni Strazzulla, Institute for Planetary Exploration, Deutsches Zentrum for Luft und Raumfahrt, INAF-Osservatorio Astrofisico di Catania (INAF-OACt), Astronomical Institute of Kharkov National University, INAF-Osservatorio Astronomico di Roma (INAF-OAR), 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, and 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)

Subjects
chemistry.chemical_classification, Materials science, Analytical chemistry, Organic chemistry, Astronomy and Astrophysics, Space weathering, Silicate, Spectral line, Ion, chemistry.chemical_compound, Ion implantation, Hydrocarbon, chemistry, Space and Planetary Science, Spectral slope, infrared, Astrophysics::Earth and Planetary Astrophysics, Irradiation, Radiation chemistry, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy
Abstract

International audience; Most ion irradiation experiments relevant to primitive outer Solar System objects have been performed on ice and silicate targets. Here we present the first ion irradiation experiments performed on natural complex hydrocarbons (asphaltite and kerite). These materials are very dark in the visible and have red-sloped spectra in the visible and near-infrared. They may be comparable in composition and structure to refractory organic solids on the surfaces of primitive outer Solar System objects. We irradiated the samples with 15-400 keV H +, N +, Ar ++, and He + ions and measured their reflectance spectra in the range of 0.3-2.5 mum before ion implantation and after each irradiation step. The results show that irradiation-induced carbonization gradually neutralizes the spectral slopes of these red organic solids. This implies a similar space weathering trend for the surfaces of airless bodies optically dominated by spectrally red organic components. The reduction of spectral slope was observed in all experiments. Irradiation with 30 keV protons, which transfers energy to the target mostly via electronic (inelastic) collisions, showed lower efficiency than the heavier ions. We found that spectral alteration in our experiments increased with increasing contribution of nuclear versus electronic energy loss. This implies that nuclear (elastic) energy deposition plays an important role in changing the optical properties of irradiated refractory complex hydrocarbon materials. Finally, our results indicated that temperature variations from 40 K to room temperature did not influence the spectral properties of these complex hydrocarbon solids.

Published
2004
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