Search

Your search keyword '"S., Erard"' showing total 33 results
Start Over Author "S., Erard"
33 results on '"S., Erard"'

1. Virtual European Solar & Planetary Access (VESPA): A Planetary Science Virtual Observatory Cornerstone

Author

S. Erard, B. Cecconi, P. Le Sidaner, C. Chauvin, A. P. Rossi, M. Minin, T. Capria, S. Ivanovski, B. Schmitt, V. Génot, N. André, C. Marmo, A. C. Vandaele, L. Trompet, M. Scherf, R. Hueso, A. Määttänen, B. Carry, N. Achilleos, J. Soucek, D. Pisa, K. Benson, P. Fernique, and E. Millour

Subjects
virtual observatory, solar system, gis, Science (General), Q1-390
Abstract

The Europlanet-2020 programme, which ended on Aug 31st, 2019, included an activity called VESPA (Virtual European Solar and Planetary Access), which focused on adapting Virtual Observatory (VO) techniques to handle Planetary Science data. This paper describes some aspects of VESPA at the end of this 4-years development phase and at the onset of the newly selected Europlanet-2024 programme starting in 2020. The main objectives of VESPA are to facilitate searches both in big archives and in small databases, to enable data analysis by providing simple data access and online visualization functions, and to allow research teams to publish derived data in an interoperable environment as easily as possible. VESPA encompasses a wide scope, including surfaces, atmospheres, magnetospheres and planetary plasmas, small bodies, heliophysics, exoplanets, and spectroscopy in solid phase. This system relies in particular on standards and tools developed for the Astronomy VO (IVOA) and extends them where required to handle specificities of Solar System studies. It also aims at making the VO compatible with tools and protocols developed in different contexts, for instance GIS for planetary surfaces, or time series tools for plasma-related measurements. An essential part of the activity is to publish a significant amount of high-quality data in this system, with a focus on derived products resulting from data analysis or simulations.

Published
2020
Full Text
View/download PDF

2. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author

F. Capaccioni, A. Coradini, G. Filacchione, S. Erard, G. Arnold, P. Drossart, M. C. De Sanctis, D. Bockelee-Morvan, M. T. Capria, F. Tosi, C. Leyrat, B. Schmitt, E. Quirico, P. Cerroni, V. Mennella, A. Raponi, M. Ciarniello, T. McCord, L. Moroz, E. Palomba, E. Ammannito, M. A. Barucci, G. Bellucci, J. Benkhoff, J. P. Bibring, A. Blanco, M. Blecka, R. Carlson, U. Carsenty, L. Colangeli, M. Combes, M. Combi, J. Crovisier, T. Encrenaz, C. Federico, U. Fink, S. Fonti, W. H. Ip, P. Irwin, R. Jaumann, E. Kuehrt, Y. Langevin, G. Magni, S. Mottola, V. Orofino, P. Palumbo, G. Piccioni, U. Schade, F. Taylor, D. Tiphene, G. P. Tozzi, P. Beck, N. Biver, L. Bonal, J.-Ph. Combe, D. Despan, E. Flamini, S. Fornasier, A. Frigeri, D. Grassi, M. Gudipati, A. Longobardo, K. Markus, F. Merlin, R. Orosei, G. Rinaldi, K. Stephan, M. Cartacci, A. Cicchetti, S. Giuppi, Y. Hello, F. Henry, S. Jacquinod, R. Noschese, G. Peter, R. Politi, J. M. Reess, and A. Semery

Published
2015
Full Text
View/download PDF

3. Erratum: Comet 67P outbursts and quiescent coma at 1.3 au from the Sun: dust properties from Rosetta/VIRTIS-H observations

Author

Dominique Bockelée-Morvan, G Rinaldi, S Erard, C Leyrat, F Capaccioni, P Drossart, G Filacchione, A Migliorini, E Quirico, S Mottola, G Tozzi, G Arnold, N Biver, M Combes, J Crovisier, A Longobardo, M Blecka, M-T Capria, 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), IASI (IASI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Istituto Fisica Spazio Interplanetario, Dysoxie, suractivité : aspects cellulaires et intégratifs thérapeutiques (DS-ACI / UMR MD2), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Consiglio Nazionale delle Ricerche (CNR), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), and bibliotheque, la.

Subjects
[PHYS]Physics [physics], Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, comets: general, Leitungsbereich PF, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, [PHYS] Physics [physics], 13. Climate action, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], infrared: planetary systems, 010303 astronomy & astrophysics, addenda, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, errata, 0105 earth and related environmental sciences
Abstract

The paper 'Comet 67P outbursts and quiescent coma at 1.3 AU from the Sun: dust properties from Rosetta/VIRTIS-H observations' was published in MNRAS 469, S443 (2017). While performing a follow-up investigation, we discovered a numerical error in the algorithms that were developed to model the infrared continuum emission from a population of dust particles. The results of the scattering models for compact or moderately porous grains (Mie theory) and fluffy grains (Rayleigh-Gans-Debye theory, RGD) are both affected. Though the general conclusions of the paper are unchanged, the quantitative constraints obtained on the dust size distribution in the quiescent coma are slightly different.

Published
2018
Full Text
View/download PDF

5. Evolution of CO 2 , CH 4 , and OCS abundances relative to H 2 O in the coma of comet 67P around perihelion from Rosetta /VIRTIS-H observations

Author

Gianrico Filacchione, Michael R. Combi, M. Combes, Fabrizio Capaccioni, Uwe Fink, Gabriele Arnold, N. Biver, S. Erard, C. Leyrat, M. T. Capria, Alessandra Migliorini, T. Encrenaz, G. P. Tozzi, Bernard Schmitt, Dominique Bockelée-Morvan, W-H. Ip, Ekkehard Kührt, Jacques Crovisier, Pierre Drossart, M. C. De Sanctis, Nicolas Fougere, G. Piccioni, 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 Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), 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]), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Physics [Imperial College London], Imperial College London, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), INAF - Osservatorio Astrofisico di Arcetri (OAA), ITA, USA, FRA, and DEU

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Astrobiology, comets: general: comets: individual: 67P/Churyumov–Gerasimenko: infrared: planetary systems, 13. Climate action, Space and Planetary Science, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

Infrared observations of the coma of 67P/Churyumov-Gerasimenko were carried out from July to September 2015, i.e., around perihelion (13 August 2015), with the high-resolution channel of the VIRTIS instrument onboard Rosetta. We present the analysis of fluorescence emission lines of H$_2$O, CO$_2$, $^{13}$CO$_2$, OCS, and CH$_4$ detected in limb sounding with the field of view at 2.7-5 km from the comet centre. Measurements are sampling outgassing from the illuminated southern hemisphere, as revealed by H$_2$O and CO$_2$ raster maps, which show anisotropic distributions, aligned along the projected rotation axis. An abrupt increase of water production is observed six days after perihelion. In the mean time, CO$_2$, CH$_4$, and OCS abundances relative to water increased by a factor of 2 to reach mean values of 32%, 0.47%, and 0.18%, respectively, averaging post-perihelion data. We interpret these changes as resulting from the erosion of volatile-poor surface layers. Sustained dust ablation due to the sublimation of water ice maintained volatile-rich layers near the surface until at least the end of the considered period, as expected for low thermal inertia surface layers. The large abundance measured for CO$_2$ should be representative of the 67P nucleus original composition, and indicates that 67P is a CO$_2$-rich comet. Comparison with abundance ratios measured in the northern hemisphere shows that seasons play an important role in comet outgassing. The low CO$_2$/H$_2$O values measured above the illuminated northern hemisphere are not original, but the result of the devolatilization of the uppermost layers., Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2016
Full Text
View/download PDF

6. Phyllosilicates on Mars and implications for early martian climate

Author

F, Poulet, J-P, Bibring, J F, Mustard, A, Gendrin, N, Mangold, Y, Langevin, R E, Arvidson, B, Gondet, C, Gomez, M, Berthé, S, Erard, O, Forni, N, Manaud, G, Poulleau, A, Soufflot, M, Combes, P, Drossart, T, Encrenaz, T, Fouchet, R, Melchiorri, G, Bellucci, F, Altieri, V, Formisano, S, Fonti, F, Capaccioni, P, Cerroni, A, Coradini, O, Korablev, V, Kottsov, N, Ignatiev, D, Titov, L, Zasova, P, Pinet, B, Schmitt, C, Sotin, E, Hauber, H, Hoffmann, R, Jaumann, U, Keller, F, Forget, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CRINON, Evelyne

Subjects
Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Climate, Iron, Mars, 01 natural sciences, Astrobiology, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, Magnesium, Composition of Mars, Spacecraft, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Martian, Mineral hydration, Multidisciplinary, Mineral, Sulfates, Noachian, Water, Mars Exploration Program, Hydrogen-Ion Concentration, Space Flight, CRISM, 13. Climate action, Clay, Hesperian, Aluminum Silicates, [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology, Geology
Abstract

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected-phyllosilicates and sulphates--result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed.

Published
2005
Full Text
View/download PDF

7. Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author

F, Capaccioni, A, Coradini, G, Filacchione, S, Erard, G, Arnold, P, Drossart, M C, De Sanctis, D, Bockelee-Morvan, M T, Capria, F, Tosi, C, Leyrat, B, Schmitt, E, Quirico, P, Cerroni, V, Mennella, A, Raponi, M, Ciarniello, T, McCord, L, Moroz, E, Palomba, E, Ammannito, M A, Barucci, G, Bellucci, J, Benkhoff, J P, Bibring, A, Blanco, M, Blecka, R, Carlson, U, Carsenty, L, Colangeli, M, Combes, M, Combi, J, Crovisier, T, Encrenaz, C, Federico, U, Fink, S, Fonti, W H, Ip, P, Irwin, R, Jaumann, E, Kuehrt, Y, Langevin, G, Magni, S, Mottola, V, Orofino, P, Palumbo, G, Piccioni, U, Schade, F, Taylor, D, Tiphene, G P, Tozzi, P, Beck, N, Biver, L, Bonal, J-Ph, Combe, D, Despan, E, Flamini, S, Fornasier, A, Frigeri, D, Grassi, M, Gudipati, A, Longobardo, K, Markus, F, Merlin, R, Orosei, G, Rinaldi, K, Stephan, M, Cartacci, A, Cicchetti, S, Giuppi, Y, Hello, F, Henry, S, Jacquinod, R, Noschese, G, Peter, R, Politi, J M, Reess, and A, Semery

Abstract

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Published
2015

8. The light curve of asteroid 2867 Steins measured by VIRTIS-M during the Rosetta fly-by

Author

F. Tosi, A. Coradini, F. Capaccioni, G. Filacchione, D. Grassi, M.C. De Sanctis, M.T. Capria, M.A. Barucci, M. Fulchignoni, S. Mottola, S. Erard, E. Dotto, C. Baldetti, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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), DLR - German Aerospace Center, and INAF-Osservatorio Astronomico di Roma (INAF-OAR)

Subjects
Rotation period, Physics, Infrared, Comet, Imaging spectrometer, Astronomy, Astronomy and Astrophysics, Asteroids Asteroid rotation Spectrophotometry Infrared observations, Light curve, Wavelength, Phase angle (astronomy), Space and Planetary Science, Asteroid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; On 5 September 2008, the Rosetta spacecraft encountered the asteroid 2867 Steins on its way to the comet 67P/Churyumov-Gerasimenko. This was the first of two planned asteroid fly-bys performed by the probe, the second fly-by being with the much larger asteroid 21 Lutetia in July 2010. The VIRTIS imaging spectrometer (IFOV 0.250 mrad, overall spectral range 0.25-5.1 mum) onboard Rosetta acquired data of Steins already before the closest approach phase, when the target was spatially unresolved, in order to obtain a light curve of the asteroid in the infrared spectral range extending up to 5 mum, that was never explored before. The VIRTIS light curve campaign started at 11:30 UTC onboard time, when the spacecraft was about 221,377 km away from the target, and ended at 17:58 UTC, at a distance of 20,741 km away from Steins. During this timeframe, the solar phase angle of the asteroid was roughly constant, ranging from 38.2° to 36.3°. Assuming the most recent value derived for the rotational period of Steins ( Lamy et al., 2008), the VIRTIS observations covered slightly more than one rotation of the asteroid. In this interval, VIRTIS collected 8 hyperspectral cubes where Steins was captured 119 times, both in the visual and in the infrared range. Given the low signal and the unresolved appearance of the source, for which the instrument was not designed, only a small subset of wavelengths turned out to be suitable to sample the light curve. Nevertheless, in both the VIS and NIR ranges we find a similar trend, with two different maxima and minima during one rotational period, and amplitudes consistent with the results in the visual range obtained in previous works, including the data set acquired by the OSIRIS camera onboard Rosetta. We also report the presence of a new broad feature centered at approximately 0.81-0.82 mum, which is seen in the visual data throughout the rotation of the asteroid.

Published
2010
Full Text
View/download PDF

9. Limb observations of CO2 and CO non-LTE emissions in the Venus atmosphere by VIRTIS/Venus Express

Author

A. Cardesín Moinelo, Miguel Lopez-Valverde, Giuseppe Piccioni, P. Drossart, S. Erard, Gabriella Gilli, Instituto de Astrofisica de Andalucia, CSIC (IAA), 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), and Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma)

Subjects
Atmospheric Science, Daytime, Infrared, Solar zenith angle, Soil Science, Venus, Aquatic Science, Oceanography, Atmospheric sciences, Mesosphere, Atmosphere, Atmosphere of Venus, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Earth-Surface Processes, Water Science and Technology, Ecology, biology, Paleontology, Astronomy, Forestry, biology.organism_classification, Geophysics, Space and Planetary Science, Environmental science, Thermosphere, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We report and analyze here observations of strong infrared emissions from the limb of the Venus upper atmosphere during daytime, taken by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard Venus Express. We focus on the measurements taken during the first 4 months of nominal operations. The emissions observed at 4.3 mum and at 2.7 mum are attributed to CO2 fluorescence of solar radiation and are detected up to about 160 km and 130 km, respectively, while the CO fluorescence at 4.7 mum is observed up to about 120 km. The emissions are detected in both the channels of VIRTIS, at different spatial and spectral resolutions (resolving powers about 1800 and 400), for the periapsis and the apoapsis of the Venus Express orbit. From these data sets we built up 2-D maps of the emissions as well as vertical profiles, which are then studied in order to characterize their variations with geophysical parameters, like solar illumination and emission altitude. Several analyses are performed in order to understand the VIRTIS behavior, to determine systematic effects in the data, and to propose appropriate corrections. We also present comparisons with a theoretical nonlocal thermodynamic equilibrium (non-LTE) model of the Venus upper atmosphere. The agreement is very encouraging, in general, and the main variability observed in the data, with solar zenith angle and altitude, can be understood with the model. We conclude that the present data set opens brilliant perspectives for deriving densities and rotational temperatures in the upper mesosphere and lower thermosphere of Venus.

Published
2009
Full Text
View/download PDF

10. Distribution of the O2 infrared nightglow observed with VIRTIS on board Venus Express

Author

Cédric Cox, S. Erard, Agustín Sánchez-Lavega, P. Drossart, Jean-Claude Gérard, Giuseppe Piccioni, Adem Saglam, Ricardo Hueso, Laboratoire de Physique Atmosphérique et Planétaire, Université de Liège (LPAP), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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 Escuela Superior de Ingeniería

Subjects
Physics, Brightness, biology, Infrared, Atmospheric circulation, Airglow, Venus, Astrophysics, Geophysics, biology.organism_classification, Atmosphere of Venus, Middle latitudes, General Earth and Planetary Sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Southern Hemisphere
Abstract

International audience; We present characteristics of the statistical horizontal distribution of the O2 infrared nightglow over most of the southern hemisphere observed with the VIRTIS instrument over a period spanning nearly 11 months of low solar activity. We show that the distribution is inhomogeneous with the regions of brightest emission reaching ~3 MegaRayleighs (MR) located at low latitude near and dawnward of the midnight meridian. The hemispherically averaged nadir brightness is 1.3 MR, in very good agreement with earlier ground based observations. We show that the dayside supply of O atoms is sufficient to produce the observed global O2 nightglow if approximately 50% of the dayside O production is carried to the nightside by the subsolar to antisolar global circulation. Limb profiles observed at northern mid-latitudes exhibit large intensity variations over short time periods. Calculations with a one-dimensional chemical diffusive model produce an airglow peak at 96 km, in agreement with the limb observations. The atomic oxygen density derived from the best fits to O2 airglow limb profiles reaches a maximum of 1.8-3.5 × 1011 cm-3 at 104 km.

Published
2008
Full Text
View/download PDF

12. A major nucleolar protein, nucleolin, induces chromatin decondensation by binding to histone H1

Author

M S, Erard, P, Belenguer, M, Caizergues-Ferrer, A, Pantaloni, and F, Amalric

Subjects
Binding Sites, Circular Dichroism, Molecular Sequence Data, Nuclear Proteins, RNA-Binding Proteins, DNA, Phosphoproteins, Chromatin, Chromatography, Affinity, Peptide Fragments, Histones, Structure-Activity Relationship, Amino Acid Sequence, Phosphorylation
Abstract

Using circular dichroism to probe the extent of DNA condensation in chromatin, we have demonstrated that a major nucleolar protein, nucleolin can decondense chromatin. By means of various binding assays we show that nucleolin has a strong affinity for histone H1 and that the phosphorylated N-terminal domain, rich in lengthy stretches of acidic amino acids, is responsible for this ionic interaction. Additional experiments clearly demonstrate that nucleolin is unable to act as a nucleosome core assembly or disassembly factor and hence has little affinity for the core histone octamer. We propose that this nucleolar protein induces chromatin decondensation by binding to histone H1, and that nucleolin can therefore be regarded as a protein of the high-mobility-group type.

Published
1988

13. Refractory and semi-volatile organics at the surface of comet 67P/Churyumov-Gerasimenko: Insights from the VIRTIS/Rosetta imaging spectrometer

Author

Quirico, E, Moroz, LV, Schmitt, B, Arnold, G, Faure, M, Beck, P, Bonal, L, Ciarniello, M, Capaccioni, F, Filacchione, G, Erard, S, Leyrat, C, Bockelee-Morvan, D, Zinzi, A, Palomba, E, Drossart, P, Tosi, F, Capria, MT, De Sanctis, MC, Raponi, A, Fonti, S, Mancarella, F, Orofino, V, Barucci, A, Blecka, MI, Carlson, R, Despan, D, Faure, A, Fornasier, S, Gudipati, MS, Longobardo, A, Markus, K, Mennella, V, Merlin, F, Piccioni, G, Rousseau, B, Taylor, F, Team, Rosetta VIRTIS, 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), 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), Agenzia Spaziale Italiana (ASI), Dipartimento di Fisica, Università degli studi di Lecce, Department of Physics [Lecce], Università del Salento [Lecce], 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), JDS Uniphase/Cronos, USA, JDS Uniphase/Cronos, 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]), Université Sciences et Technologies - Bordeaux 1 (UB)-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, 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), 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), E., Quirico, L. V., Moroz, B., Schmitt, G., Arnold, M., Faure, P., Beck, L., Bonal, M., Ciarniello, F., Capaccioni, G., Filacchione, S., Erard, C., Leyrat, D., Bockelée Morvan, A., Zinzi, E., Palomba, P., Drossart, F., Tosi, M. T., Capria, M. C., De Sancti, A., Raponi, Fonti, Sergio, Mancarella, Francesca, Orofino, Vincenzo, A., Barucci, M. I., Blecka, R., Carlson, D., Despan, A., Faure, S., Fornasier, M. S., Gudipati, A., Longobardo, K., Marku, V., Mennella, F., Merlin, G., Piccioni, B., Rousseau, F., Taylor, ITA, USA, GBR, FRA, DEU, and POL

Subjects
Solar System, Institut für Erd- und Umweltwissenschaften, Materials science, 010504 meteorology & atmospheric sciences, Infrared, Comet, Imaging spectrometer, Organic chemistry, 01 natural sciences, Spectral line, Astrobiology, Chondrite, 0103 physical sciences, Comets, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Infrared observations, Interstellar ice, Astronomy and Astrophysics, Spectrophotometry, 13. Climate action, Space and Planetary Science, Absorption band, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Meteorites
Abstract

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument aboard the Rosetta spacecraft has performed extensive spectral mapping of the surface of comet 67P/Churyumov-Gerasimenko in the range 0.3-5 mu m. The reflectance spectra collected across the surface display a low reflectance factor over the whole spectral range, two spectral slopes in the visible and near-infrared ranges and a broad absorption band centered at 3.2 mu m. The first two of these characteristics are typical of dark small bodies of the Solar System and are difficult to interpret in terms of composition. Moreover, solar wind irradiation may modify the structure and composition of surface materials and there is no unequivocal interpretation of these spectra devoid of vibrational bands. To circumvent these problems, we consider the composition of cometary grains analyzed in the laboratory to constrain the nature of the cometary materials and consider results on surface rejuvenation and solar wind processing provided by the OSIRIS and ROSINA instruments, respectively. Our results lead to five main conclusions: (i) The low albedo of comet 67P/CG is accounted for by a dark refractory polyaromatic carbonaceous component mixed with opaque minerals. VIRTIS data do not provide direct insights into the nature of these opaque minerals. However, according to the composition of cometary grains analyzed in the laboratory, we infer that they consist of Fe-Ni alloys and FeS sulfides. (ii) A semi-volatile component, consisting of a complex mix of low weight molecular species not volatilized at T similar to 220 K, is likely a major carrier of the 3.2 p.m band. Water ice contributes significantly to this feature in the neck region but not in other regions of the comet. COOH in carboxylic acids is the only chemical group that encompasses the broad width of this feature. It appears as a highly plausible candidate along with the NH4+ ion. (iii) Photolytic/thermal residues, produced in the laboratory from interstellar ice analogs, are potentially good spectral analogs. (iv) No hydrated minerals were identified and our data support the lack of genetic links with the CI, CR and CM primitive chondrites. This concerns in particular the Orgueil chondrite, previously suspected to have been of cometary origin. (v) The comparison between fresh and aged terrains revealed no effect of solar wind irradiation on the 3.2 mu m band. This is consistent with the presence of efficient resurfacing processes such as dust transport from the interior to the surface, as revealed by the OSIRIS camera. (C) 2016 Elsevier Inc. All rights reserved.

Published
2016
Full Text
View/download PDF

14. Exposed water ice on the nucleus of comet 67P/Churyumov-Gerasimenko

Author

Giancarlo Bellucci, Katrin Stephan, Yves Langevin, Sergio Fonti, G. Peter, Gianrico Filacchione, Ulrich Schade, G. P. Tozzi, Jacques Crovisier, Costanzo Federico, Eleonora Ammannito, M. I. Blecka, S. Jacquinod, Jean-Michel Reess, M. Cartacci, Michael R. Combi, Vito Mennella, Federico Tosi, Marcello Fulchignoni, Armando Blanco, Giuseppe Piccioni, Roberto Orosei, Bernard Schmitt, Andrea Longobardo, Giovanna Rinaldi, Ralf Jaumann, Vincenzo Orofino, Alessandra Migliorini, Andrea Raponi, Pierre Drossart, M. Combes, David Kappel, Mauro Ciarniello, D. Despan, Murthy S. Gudipati, C. Leyrat, T. Encrenaz, Ernesto Palomba, Andrea Cicchetti, Fabrizio Capaccioni, Michelangelo Formisano, Maria Teresa Capria, Romolo Politi, Dominique Bockelée-Morvan, Stefano Mottola, Enrico Flamini, Pierre Beck, L. Moroz, Gianfranco Magni, U. Fink, Eric Quirico, Fredric W. Taylor, Sonia Fornasier, J-Ph. Combe, F. Merlin, Jean-Pierre Bibring, N. Biver, M. C. De Sanctis, Florence Henry, Uri Carsenty, M. A. Barucci, Gabriele Arnold, Y. Hello, Patrick G. J. Irwin, R. W. Carlson, Wing-Huen Ip, E. Kuehrt, Kathrin Markus, Davide Grassi, S. Giuppi, Raffaella Noschese, Alessandro Frigeri, F. Mancarella, Stéphane Erard, Luigi Colangeli, Lydie Bonal, T. B. McCord, J. Benkhoff, D. Tiphene, Priscilla Cerroni, G., Filacchione, M. C., De Sancti, F., Capaccioni, A., Raponi, F., Tosi, M., Ciarniello, P., Cerroni, G., Piccioni, M. T., Capria, E., Palomba, G., Bellucci, S., Erard, D., Bockelee Morvan, C., Leyrat, G., Arnold, M. A., Barucci, M., Fulchignoni, B., Schmitt, E., Quirico, R., Jaumann, K., Stephan, A., Longobardo, V., Mennella, A., Migliorini, E., Ammannito, J., Benkhoff, J. P., Bibring, Blanco, Armando, M. I., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, M., Combi, J., Crovisier, P., Drossart, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, W. H., Ip, P., Irwin, E., Kuehrt, Y., Langevin, G., Magni, T., Mccord, L., Moroz, S., Mottola, Orofino, Vincenzo, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, P., Beck, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, M., Formisano, S., Fornasier, A., Frigeri, D., Grassi, M. S., Gudipati, D., Kappel, Mancarella, Francesca, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, J. M., Ree, R., Noschese, R., Politi, G., Peter, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), 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), Laboratoire de Physique et Mécanique Textiles (LPMT), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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]), German Aerospace Center (DLR), Deutsches Zentrum für Luft- und Raumfahrt (DLR), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), 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), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Capodimonte (OAC), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Instituto de Estudos Avançados (IEAV), Institut, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Dipartimento di Fisica, Università degli studi di Lecce, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Physics [Oxford], University of Oxford, Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], DLR Institute of Planetary Research, Department of Physics [Lecce], Università del Salento [Lecce], INAF - Osservatorio Astrofisico di Arcetri (OAA), 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), Alenia Aerospazio, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), JDS Uniphase/Cronos, USA, JDS Uniphase/Cronos, CNR-IASF, Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Consiglio Nazionale delle Ricerche (CNR), 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), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-ENSITM-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Polska Akademia Nauk (PAN), University of Oxford [Oxford], 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), Centre National de la Recherche Scientifique (CNRS), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), ENSITM-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 010504 meteorology & atmospheric sciences, Extraterrestrial Environment, Comet, Mineralogy, comet 67P, 01 natural sciences, water ice, Astrobiology, Diffusion, 0103 physical sciences, Rosetta, medicine, Diffusion (business), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Meteoroid, Spectrum Analysis, Ice, food and beverages, Meteoroids, VIRTIS, Debris, Asteroids, Grain growth, medicine.anatomical_structure, 13. Climate action, comets and Kuiper belt Early solar system, Gases, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Water vapor
Abstract

Although water vapour is the main species observed in the coma of comet 67P/Churyumov–Gerasimenko1, 2 and water is the major constituent of cometary nuclei3, 4, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far5, 6. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far7, 8, 9. The nucleus of 67P/Churyumov–Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material10. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations6, 7, 8, 9. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers6, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust10 is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov–Gerasimenko11, 12 is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet’s formation.

Published
2016
Full Text
View/download PDF

15. Laboratory measurement supporting VIRTIS-M data on 67P/CG

Author

Mancarella, F., Fonti, S., Orofino, V., Capaccioni, F., Filacchione, G., Erard, S., Bockelee-Morvan, D., Leyrat, C., Arnold, Gabriele, Piccioni, G., Longobardo, A, Tosi, F., Mancarella, Francesca, Fonti, Sergio, Orofino, Vincenzo, F., Capaccioni, G., Filacchione, S., Erard, D., Bockelée Morvan, C., Leyrat, G., Arnold, G., Piccioni, A., Longobardo, and F., Tosi

Subjects
67P, composition, Leitungsbereich PF, Rosetta, VIRTIS
Abstract

Among the primary goals of the VIRTIS instrument onboard ESA Rosetta mission is to provide the surface composition of the comet 67P/Churyumov- Gerasimenko. The objective of this work is to discuss the needed laboratory measurements on particulate samples supporting the interpretation of the VIRTIS- M spectra.

Published
2015

16. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author

Gabriele Arnold, Maria Teresa Capria, Y. Hello, Kathrin Markus, Vincenzo Orofino, A. Semery, Romolo Politi, Stéphane Erard, Roberto Orosei, Robert W. Carlson, Davide Grassi, M. Combes, J. Crovisier, Gianfranco Magni, Andrea Raponi, Michael R. Combi, Priscilla Cerroni, Yves Langevin, L. Moroz, Pierre Drossart, Ulrich Schade, G. P. Tozzi, Wing-Huen Ip, Luigi Colangeli, Fredric W. Taylor, Angioletta Coradini, J. Ph. Combe, Raffaella Noschese, Enrico Flamini, Giancarlo Bellucci, Ernesto Palomba, Sonia Fornasier, F. Merlin, Lydie Bonal, Andrea Longobardo, G. Peter, M. Cartacci, Alessandro Frigeri, Giuseppe Piccioni, Bernard Schmitt, Uwe Fink, Ralf Jaumann, Mauro Ciarniello, D. Despan, M. A. Barucci, Giovanna Rinaldi, Pierre Beck, M. C. De Sanctis, S. Giuppi, S. Jacquinod, Uri Carsenty, D. Bockelee-Morvan, Eric Quirico, Stefano Mottola, F. Henry, N. Biver, Jean-Pierre Bibring, Patrick G. J. Irwin, T. Encrenaz, Katrin Stephan, Andrea Cicchetti, Johannes Benkhoff, C. Leyrat, Gianrico Filacchione, D. Tiphene, J. M. Reess, T. B. McCord, Sergio Fonti, Costanzo Federico, Eleonora Ammannito, M. I. Blecka, Pasquale Palumbo, Armando Blanco, M. Gudipati, Fabrizio Capaccioni, Vito Mennella, Federico Tosi, E. Kuehrt, F., Capaccioni, A., Coradini, G., Filacchione, S., Erard, G., Arnold, P., Drossart, M. C., De Sancti, D., Bockelee Morvan, M. T., Capria, F., Tosi, C., Leyrat, B., Schmitt, E., Quirico, P., Cerroni, V., Mennella, A., Raponi, M., Ciarniello, T., Mccord, L., Moroz, E., Palomba, E., Ammannito, M. A., Barucci, G., Bellucci, J., Benkhoff, J. P., Bibring, Blanco, Armando, M., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, M., Combi, J., Crovisier, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, W. H., Ip, P., Irwin, R., Jaumann, E., Kuehrt, Y., Langevin, G., Magni, S., Mottola, Orofino, Vincenzo, P., Palumbo, G., Piccioni, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, P., Beck, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, S., Fornasier, A., Frigeri, D., Grassi, M., Gudipati, A., Longobardo, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, K., Stephan, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, R., Noschese, G., Peter, R., Politi, J. M., Ree, A., Semery, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), 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), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), 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), Polska Akademia Nauk (PAN), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, German Aerospace Center (DLR), Department of Physics [Imperial College London], Imperial College London, Instituto de Estudos Avançados (IEAV), Institut, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Dipartimento di Fisica, Università degli studi di Lecce, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], DLR Institute of Planetary Research, Department of Physics [Lecce], Università del Salento [Lecce], INAF - Osservatorio Astrofisico di Arcetri (OAA), 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), Alenia Aerospazio, JDS Uniphase/Cronos, USA, JDS Uniphase/Cronos, CNR-IASF, IASI (IASI), Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = 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)-Centre National d’Études Spatiales [Paris] (CNES), Polska Akademia Nauk = Polish Academy of Sciences (PAN), NASA-California Institute of Technology (CALTECH), University of Oxford, 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), ITA, USA, GBR, FRA, DEU, TWN, NLD, and POL

Subjects
67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Opacity, Rosetta mission, VIRTIS, comets, Infrared, Comet, Imaging spectrometer, Astrophysics, 01 natural sciences, Astrobiology, comet, 0103 physical sciences, Spectral slope, Thermal, Rosetta, Rosetta mission, comets, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Chemistry, Albedo, VIRTIS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], organic-rich
Abstract

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ −1 ), and the broad absorption feature in the 2.9-to-3.6–micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Published
2015
Full Text
View/download PDF

17. The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko

Author

DE SANCTIS, MARIA CRISTINA, CAPACCIONI, FABRIZIO, CIARNIELLO, Mauro, FILACCHIONE, GIANRICO, FORMISANO, Michelangelo, Mottola, S., RAPONI, Andrea, TOSI, Federico, Bockelée-Morvan, D., Erard, S., Leyrat, C., Schmitt, B., Ammannito, E., Arnold, G., Barucci, M. A., Combi, M., Capria, M. T., Cerroni, P., Ip, W. -H., Kuehrt, E., McCord, T. B., PALOMBA, Ernesto, Beck, P., Quirico, E., VIRTIS Team, PICCIONI, GIUSEPPE, BELLUCCI, Giancarlo, Fulchignoni, M., Jaumann, R., Stephan, K., Longobardo, A., MENNELLA, Vito, MIGLIORINI, Alessandra, Benkhoff, J., Bibring, J. P., Blanco, A., Blecka, M., Carlson, R., Carsenty, U., Colangeli, L., Combes, M., Crovisier, J., Drossart, P., Encrenaz, T., Federico, C., Fink, U., Fonti, S., Irwin, P., Langevin, Y., Magni, G., Moroz, L., Orofino, V., Schade, U., Taylor, F., Tiphene, D., Tozzi, G. P., Biver, N., Bonal, L., Combe, J. -Ph., Despan, D., Flamini, E., Fornasier, S., FRIGERI, ALESSANDRO, GRASSI, Davide, Gudipati, M. S., Mancarella, F., Markus, K., Merlin, F., OROSEI, ROBERTO, RINALDI, GIOVANNA, CARTACCI, MARCO, Cicchetti, A., GIUPPI, Stefano, Hello, Y., Henry, F., Jacquinod, S., Rees, J. M., NOSCHESE, RAFFAELLA, POLITI, ROMOLO, Peter, G., M. C., De Sancti, F., Capaccioni, M., Ciarniello, G., Filacchione, M., Formisano, S., Mottola, A., Raponi, F., Tosi, D., Bockele´e Morvan, S., Erard, C., Leyrat, B., Schmitt, E., Ammannito, G., Arnold, M. A., Barucci, M., Combi, M. T., Capria, P., Cerroni, W. H., Ip, E., Kuehrt, T. B., Mccord, E., Palomba, P., Beck, E., Quirico, G., Piccioni, G., Bellucci, M., Fulchignoni, R., Jaumann, K., Stephan, A., Longobardo, V., Mennella, A., Migliorini, J., Benkhoff, J. P., Bibring, Blanco, Armando, M., Blecka, R., Carlson, U., Carsenty, L., Colangeli, M., Combe, J., Crovisier, P., Drossart, T., Encrenaz, C., Federico, U., Fink, Fonti, Sergio, P., Irwin, Y., Langevin, G., Magni, L., Moroz, Orofino, Vincenzo, U., Schade, F., Taylor, D., Tiphene, G. P., Tozzi, N., Biver, L., Bonal, Combe, J. P. h., D., Despan, E., Flamini, S., Fornasier, A., Frigeri, D., Grassi, M. S., Gudipati, Mancarella, Francesca, K., Marku, F., Merlin, R., Orosei, G., Rinaldi, M., Cartacci, A., Cicchetti, S., Giuppi, Y., Hello, F., Henry, S., Jacquinod, J. M., Ree, R., Noschese, R., Politi, G., Peter, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), 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), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Laboratoire de Sciences de la Terre, ITA, USA, GBR, FRA, DEU, TWN, NLD, POL, and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
67P/Churyumov-Gerasimenko, Time Factors, Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Comet, 01 natural sciences, water ice, Astrobiology, comet, Diurnal cycle, 0103 physical sciences, Sunrise, Water cycle, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Multidisciplinary, Meteoroid, Ice, Diurnal temperature variation, Temperature, food and beverages, Meteoroids, Environmental science, Volatilization, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Surface water, cycle of water ice, Water vapor
Abstract

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

Published
2015
Full Text
View/download PDF

18. Geometric preprocessing for measurements of comet 67P acquired by Rosetta's Visible and InfraRed Thermal Imaging Spectrometer, Mapping channel (VIRTIS-M).

Author

Kappel D, Arnold G, Filacchione G, Capaccioni F, Tosi F, Erard S, Ciarniello M, D'Aversa E, Raponi A, Leyrat C, and Moroz LV

Abstract

Comet 67P/Churyumov-Gerasimenko (hereafter 67P) was the primary target of ESA's Rosetta mission. Hyperspectral images acquired by the Mapping channel of the Visible and InfraRed Thermal Imaging Spectrometer aboard Rosetta can be used to derive physical and compositional surface properties by detailed spectrophotometric analyses. This calls for a precise spatial co-registration between measurements and geometry information. In this work, we improve the wavelength-dependent co-registration and also the spatial consistency of the radiometric calibration. This is accomplished by applying a feature-based image matching method comparing measured 67P nucleus images from the entire mission to corresponding photometric simulations. The derived geometric distortions suggest previously unaccounted optical aberrations of the instrument, in conjunction with non-systematic spacecraft pointing and perspective errors, and discrepancies between the true nucleus shape at data acquisition time and the used digital shape model., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).)

Published
2024
Full Text
View/download PDF

19. Correction of instrument temperature dependence of detector responsivity for measurements of comet 67P acquired by Rosetta's Visible and InfraRed Thermal Imaging Spectrometer, Mapping channel (VIRTIS-M).

Author

Kappel D, Arnold G, Filacchione G, Capaccioni F, Tosi F, Erard S, Ciarniello M, D'Aversa E, Raponi A, Leyrat C, and Moroz LV

Abstract

The Mapping channel of the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS-M) aboard Rosetta acquired many hyperspectral images of comet 67P/Churyumov-Gerasimenko (hereafter 67P). The VIS channel detector responsivity was dependent on the VIS detector temperature (TVIS). This affects the absolute values of the measured spectra (for a TVIS increase of 1 K between 0.06% increase at 0.55 μm and 1.2% increase at 1 μm) and the spectral slopes. Here, we derive a simple parameterization of this CCD-typical effect based on a statistical analysis of the TVIS-related bias of the measurements. At this, we include all measured VIS spectra excluding acquisitions with little nucleus surface information or at opposition geometry, thereby achieving a high statistical significance and representativity. The corresponding VIS detector responsivity correction, slightly different for measurements acquired when the IR cryocooler was off or on, makes the spectra measured at different instrument temperatures consistent over the entire Rosetta mission phase at 67P. This will improve future quantitative analyses of the data., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).)

Published
2024
Full Text
View/download PDF

20. Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids.

Author

Poch O, Istiqomah I, Quirico E, Beck P, Schmitt B, Theulé P, Faure A, Hily-Blant P, Bonal L, Raponi A, Ciarniello M, Rousseau B, Potin S, Brissaud O, Flandinet L, Filacchione G, Pommerol A, Thomas N, Kappel D, Mennella V, Moroz L, Vinogradoff V, Arnold G, Erard S, Bockelée-Morvan D, Leyrat C, Capaccioni F, De Sanctis MC, Longobardo A, Mancarella F, Palomba E, and Tosi F

Abstract

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the basis of laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semivolatile ammonium salts are a substantial reservoir of nitrogen in the comet, potentially dominating over refractory organic matter and more volatile species. Similar absorption features appear in the spectra of some asteroids, implying a compositional link between asteroids, comets, and the parent interstellar cloud., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Published
2020
Full Text
View/download PDF

21. An orbital water-ice cycle on comet 67P from colour changes.

Author

Filacchione G, Capaccioni F, Ciarniello M, Raponi A, Rinaldi G, De Sanctis MC, Bockelèe-Morvan D, Erard S, Arnold G, Mennella V, Formisano M, Longobardo A, and Mottola S

Abstract

Solar heating of a cometary surface provides the energy necessary to sustain gaseous activity, through which dust is removed 1,2 . In this dynamical environment, both the coma 3,4 and the nucleus 5,6 evolve during the orbit, changing their physical and compositional properties. The environment around an active nucleus is populated by dust grains with complex and variegated shapes 7 , lifted and diffused by gases freed from the sublimation of surface ices 8,9 . The visible colour of dust particles is highly variable: carbonaceous organic material-rich grains 10 appear red while magnesium silicate-rich 11,12 and water-ice-rich 13,14 grains appear blue, with some dependence on grain size distribution, viewing geometry, activity level and comet family type. We know that local colour changes are associated with grain size variations, such as in the bluer jets made of submicrometre grains on comet Hale-Bopp 15 or in the fragmented grains in the coma 16 of C/1999 S4 (LINEAR). Apart from grain size, composition also influences the coma's colour response, because transparent volatiles can introduce a substantial blueing in scattered light, as observed in the dust particles ejected after the collision of the Deep Impact probe with comet 9P/Tempel 1 17 . Here we report observations of two opposite seasonal colour cycles in the coma and on the surface of comet 67P/Churyumov-Gerasimenko through its perihelion passage 18 . Spectral analysis indicates an enrichment of submicrometre grains made of organic material and amorphous carbon in the coma, causing reddening during the passage. At the same time, the progressive removal of dust from the nucleus causes the exposure of more pristine and bluish icy layers on the surface. Far from the Sun, we find that the abundance of water ice on the nucleus is reduced owing to redeposition of dust and dehydration of the surface layer while the coma becomes less red.

Published
2020
Full Text
View/download PDF

22. Seasonal exposure of carbon dioxide ice on the nucleus of comet 67P/Churyumov-Gerasimenko.

Author

Filacchione G, Raponi A, Capaccioni F, Ciarniello M, Tosi F, Capria MT, De Sanctis MC, Migliorini A, Piccioni G, Cerroni P, Barucci MA, Fornasier S, Schmitt B, Quirico E, Erard S, Bockelee-Morvan D, Leyrat C, Arnold G, Mennella V, Ammannito E, Bellucci G, Benkhoff J, Bibring JP, Blanco A, Blecka MI, Carlson R, Carsenty U, Colangeli L, Combes M, Combi M, Crovisier J, Drossart P, Encrenaz T, Federico C, Fink U, Fonti S, Fulchignoni M, Ip WH, Irwin P, Jaumann R, Kuehrt E, Langevin Y, Magni G, McCord T, Moroz L, Mottola S, Palomba E, Schade U, Stephan K, Taylor F, Tiphene D, Tozzi GP, Beck P, Biver N, Bonal L, Combe JP, Despan D, Flamini E, Formisano M, Frigeri A, Grassi D, Gudipati MS, Kappel D, Longobardo A, Mancarella F, Markus K, Merlin F, Orosei R, Rinaldi G, Cartacci M, Cicchetti A, Hello Y, Henry F, Jacquinod S, Reess JM, Noschese R, Politi R, and Peter G

Abstract

Carbon dioxide (CO 2 ) is one of the most abundant species in cometary nuclei, but because of its high volatility, CO 2 ice is generally only found beneath the surface. We report the infrared spectroscopic identification of a CO 2 ice-rich surface area located in the Anhur region of comet 67P/Churyumov-Gerasimenko. Spectral modeling shows that about 0.1% of the 80- by 60-meter area is CO 2 ice. This exposed ice was observed a short time after the comet exited local winter; following the increased illumination, the CO 2 ice completely disappeared over about 3 weeks. We estimate the mass of the sublimated CO 2 ice and the depth of the eroded surface layer. We interpret the presence of CO 2 ice as the result of the extreme seasonal changes induced by the rotation and orbit of the comet., (Copyright © 2016, American Association for the Advancement of Science.)

Published
2016
Full Text
View/download PDF

23. Exposed water ice on the nucleus of comet 67P/Churyumov-Gerasimenko.

Author

Filacchione G, De Sanctis MC, Capaccioni F, Raponi A, Tosi F, Ciarniello M, Cerroni P, Piccioni G, Capria MT, Palomba E, Bellucci G, Erard S, Bockelee-Morvan D, Leyrat C, Arnold G, Barucci MA, Fulchignoni M, Schmitt B, Quirico E, Jaumann R, Stephan K, Longobardo A, Mennella V, Migliorini A, Ammannito E, Benkhoff J, Bibring JP, Blanco A, Blecka MI, Carlson R, Carsenty U, Colangeli L, Combes M, Combi M, Crovisier J, Drossart P, Encrenaz T, Federico C, Fink U, Fonti S, Ip WH, Irwin P, Kuehrt E, Langevin Y, Magni G, McCord T, Moroz L, Mottola S, Orofino V, Schade U, Taylor F, Tiphene D, Tozzi GP, Beck P, Biver N, Bonal L, Combe JP, Despan D, Flamini E, Formisano M, Fornasier S, Frigeri A, Grassi D, Gudipati MS, Kappel D, Mancarella F, Markus K, Merlin F, Orosei R, Rinaldi G, Cartacci M, Cicchetti A, Giuppi S, Hello Y, Henry F, Jacquinod S, Reess JM, Noschese R, Politi R, and Peter G

Subjects
Diffusion, Gases analysis, Gases chemistry, Spectrum Analysis, Extraterrestrial Environment chemistry, Ice analysis, Meteoroids
Abstract

Although water vapour is the main species observed in the coma of comet 67P/Churyumov-Gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far. The nucleus of 67P/Churyumov-Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov-Gerasimenko is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet's formation.

Published
2016
Full Text
View/download PDF

24. The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko.

Author

De Sanctis MC, Capaccioni F, Ciarniello M, Filacchione G, Formisano M, Mottola S, Raponi A, Tosi F, Bockelée-Morvan D, Erard S, Leyrat C, Schmitt B, Ammannito E, Arnold G, Barucci MA, Combi M, Capria MT, Cerroni P, Ip WH, Kuehrt E, McCord TB, Palomba E, Beck P, and Quirico E

Subjects
Temperature, Time Factors, Volatilization, Extraterrestrial Environment chemistry, Ice analysis, Meteoroids
Abstract

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

Published
2015
Full Text
View/download PDF

25. Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta.

Author

Capaccioni F, Coradini A, Filacchione G, Erard S, Arnold G, Drossart P, De Sanctis MC, Bockelee-Morvan D, Capria MT, Tosi F, Leyrat C, Schmitt B, Quirico E, Cerroni P, Mennella V, Raponi A, Ciarniello M, McCord T, Moroz L, Palomba E, Ammannito E, Barucci MA, Bellucci G, Benkhoff J, Bibring JP, Blanco A, Blecka M, Carlson R, Carsenty U, Colangeli L, Combes M, Combi M, Crovisier J, Encrenaz T, Federico C, Fink U, Fonti S, Ip WH, Irwin P, Jaumann R, Kuehrt E, Langevin Y, Magni G, Mottola S, Orofino V, Palumbo P, Piccioni G, Schade U, Taylor F, Tiphene D, Tozzi GP, Beck P, Biver N, Bonal L, Combe JP, Despan D, Flamini E, Fornasier S, Frigeri A, Grassi D, Gudipati M, Longobardo A, Markus K, Merlin F, Orosei R, Rinaldi G, Stephan K, Cartacci M, Cicchetti A, Giuppi S, Hello Y, Henry F, Jacquinod S, Noschese R, Peter G, Politi R, Reess JM, and Semery A

Abstract

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun., (Copyright © 2015, American Association for the Advancement of Science.)

Published
2015
Full Text
View/download PDF

26. The surface composition and temperature of asteroid 21 Lutetia as observed by Rosetta/VIRTIS.

Author

Coradini A, Capaccioni F, Erard S, Arnold G, De Sanctis MC, Filacchione G, Tosi F, Barucci MA, Capria MT, Ammannito E, Grassi D, Piccioni G, Giuppi S, Bellucci G, Benkhoff J, Bibring JP, Blanco A, Blecka M, Bockelee-Morvan D, Carraro F, Carlson R, Carsenty U, Cerroni P, Colangeli L, Combes M, Combi M, Crovisier J, Drossart P, Encrenaz ET, Federico C, Fink U, Fonti S, Giacomini L, Ip WH, Jaumann R, Kuehrt E, Langevin Y, Magni G, McCord T, Mennella V, Mottola S, Neukum G, Orofino V, Palumbo P, Schade U, Schmitt B, Taylor F, Tiphene D, and Tozzi G

Abstract

The Visible, InfraRed, and Thermal Imaging Spectrometer (VIRTIS) on Rosetta obtained hyperspectral images, spectral reflectance maps, and temperature maps of the asteroid 21 Lutetia. No absorption features, of either silicates or hydrated minerals, have been detected across the observed area in the spectral range from 0.4 to 3.5 micrometers. The surface temperature reaches a maximum value of 245 kelvin and correlates well with topographic features. The thermal inertia is in the range from 20 to 30 joules meter(-2) kelvin(-1) second(-0.5), comparable to a lunarlike powdery regolith. Spectral signatures of surface alteration, resulting from space weathering, seem to be missing. Lutetia is likely a remnant of the primordial planetesimal population, unaltered by differentiation processes and composed of chondritic materials of enstatitic or carbonaceous origin, dominated by iron-poor minerals that have not suffered aqueous alteration.

Published
2011
Full Text
View/download PDF

27. Venus's southern polar vortex reveals precessing circulation.

Author

Luz D, Berry DL, Piccioni G, Drossart P, Politi R, Wilson CF, Erard S, and Nuccilli F

Abstract

Initial images of Venus's south pole by the Venus Express mission have shown the presence of a bright, highly variable vortex, similar to that at the planet's north pole. Using high-resolution infrared measurements of polar winds from the Venus Express Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument, we show the vortex to have a constantly varying internal structure, with a center of rotation displaced from the geographic south pole by ~3 degrees of latitude and that drifts around the pole with a period of 5 to 10 Earth days. This is indicative of a nonsymmetric and varying precession of the polar atmospheric circulation with respect to the planetary axis.

Published
2011
Full Text
View/download PDF

28. Pd-catalyzed intramolecular oxyalkynylation of alkenes with hypervalent iodine.

Author

Nicolai S, Erard S, González DF, and Waser J

Subjects
Alkynes chemistry, Catalysis, Molecular Structure, Alkenes chemistry, Alkynes chemical synthesis, Organometallic Compounds chemistry, Palladium chemistry
Abstract

The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benziodoxolone-derived hypervalent iodine reagent 3d as an alkyne transfer reagent further expands the rapidly increasing utility of hypervalent iodine reagents in catalysis and is expected to have important implications for other similar processes.

Published
2010
Full Text
View/download PDF

29. A dynamic upper atmosphere of Venus as revealed by VIRTIS on Venus Express.

Author

Drossart P, Piccioni G, Gérard JC, Lopez-Valverde MA, Sanchez-Lavega A, Zasova L, Hueso R, Taylor FW, Bézard B, Adriani A, Angrilli F, Arnold G, Baines KH, Bellucci G, Benkhoff J, Bibring JP, Blanco A, Blecka MI, Carlson RW, Coradini A, Di Lellis A, Encrenaz T, Erard S, Fonti S, Formisano V, Fouchet T, Garcia R, Haus R, Helbert J, Ignatiev NI, Irwin P, Langevin Y, Lebonnois S, Luz D, Marinangeli L, Orofino V, Rodin AV, Roos-Serote MC, Saggin B, Stam DM, Titov D, Visconti G, Zambelli M, Tsang C, Ammannito E, Barbis A, Berlin R, Bettanini C, Boccaccini A, Bonnello G, Bouyé M, Capaccioni F, Cardesin A, Carraro F, Cherubini G, Cosi M, Dami M, De Nino M, Del Vento D, Di Giampietro M, Donati A, Dupuis O, Espinasse S, Fabbri A, Fave A, Veltroni IF, Filacchione G, Garceran K, Ghomchi Y, Giustizi M, Gondet B, Hello Y, Henry F, Hofer S, Huntzinger G, Kachlicki J, Knoll R, Kouach D, Mazzoni A, Melchiorri R, Mondello G, Monti F, Neumann C, Nuccilli F, Parisot J, Pasqui C, Perferi S, Peter G, Piacentino A, Pompei C, Réess JM, Rivet JP, Romano A, Russ N, Santoni M, Scarpelli A, Sémery A, Soufflot A, Stefanovitch D, Suetta E, Tarchi F, Tonetti N, Tosi F, and Ulmer B

Abstract

The upper atmosphere of a planet is a transition region in which energy is transferred between the deeper atmosphere and outer space. Molecular emissions from the upper atmosphere (90-120 km altitude) of Venus can be used to investigate the energetics and to trace the circulation of this hitherto little-studied region. Previous spacecraft and ground-based observations of infrared emission from CO2, O2 and NO have established that photochemical and dynamic activity controls the structure of the upper atmosphere of Venus. These data, however, have left unresolved the precise altitude of the emission owing to a lack of data and of an adequate observing geometry. Here we report measurements of day-side CO2 non-local thermodynamic equilibrium emission at 4.3 microm, extending from 90 to 120 km altitude, and of night-side O2 emission extending from 95 to 100 km. The CO2 emission peak occurs at approximately 115 km and varies with solar zenith angle over a range of approximately 10 km. This confirms previous modelling, and permits the beginning of a systematic study of the variability of the emission. The O2 peak emission happens at 96 km +/- 1 km, which is consistent with three-body recombination of oxygen atoms transported from the day side by a global thermospheric sub-solar to anti-solar circulation, as previously predicted.

Published
2007
Full Text
View/download PDF

30. South-polar features on Venus similar to those near the north pole.

Author

Piccioni G, Drossart P, Sanchez-Lavega A, Hueso R, Taylor FW, Wilson CF, Grassi D, Zasova L, Moriconi M, Adriani A, Lebonnois S, Coradini A, Bézard B, Angrilli F, Arnold G, Baines KH, Bellucci G, Benkhoff J, Bibring JP, Blanco A, Blecka MI, Carlson RW, Di Lellis A, Encrenaz T, Erard S, Fonti S, Formisano V, Fouchet T, Garcia R, Haus R, Helbert J, Ignatiev NI, Irwin PG, Langevin Y, Lopez-Valverde MA, Luz D, Marinangeli L, Orofino V, Rodin AV, Roos-Serote MC, Saggin B, Stam DM, Titov D, Visconti G, Zambelli M, Ammannito E, Barbis A, Berlin R, Bettanini C, Boccaccini A, Bonnello G, Bouye M, Capaccioni F, Moinelo AC, Carraro F, Cherubini G, Cosi M, Dami M, De Nino M, Del Vento D, Di Giampietro M, Donati A, Dupuis O, Espinasse S, Fabbri A, Fave A, Veltroni IF, Filacchione G, Garceran K, Ghomchi Y, Giustini M, Gondet B, Hello Y, Henry F, Hofer S, Huntzinger G, Kachlicki J, Knoll R, Driss K, Mazzoni A, Melchiorri R, Mondello G, Monti F, Neumann C, Nuccilli F, Parisot J, Pasqui C, Perferi S, Peter G, Piacentino A, Pompei C, Reess JM, Rivet JP, Romano A, Russ N, Santoni M, Scarpelli A, Semery A, Soufflot A, Stefanovitch D, Suetta E, Tarchi F, Tonetti N, Tosi F, and Ulmer B

Abstract

Venus has no seasons, slow rotation and a very massive atmosphere, which is mainly carbon dioxide with clouds primarily of sulphuric acid droplets. Infrared observations by previous missions to Venus revealed a bright 'dipole' feature surrounded by a cold 'collar' at its north pole. The polar dipole is a 'double-eye' feature at the centre of a vast vortex that rotates around the pole, and is possibly associated with rapid downwelling. The polar cold collar is a wide, shallow river of cold air that circulates around the polar vortex. One outstanding question has been whether the global circulation was symmetric, such that a dipole feature existed at the south pole. Here we report observations of Venus' south-polar region, where we have seen clouds with morphology much like those around the north pole, but rotating somewhat faster than the northern dipole. The vortex may extend down to the lower cloud layers that lie at about 50 km height and perhaps deeper. The spectroscopic properties of the clouds around the south pole are compatible with a sulphuric acid composition.

Published
2007
Full Text
View/download PDF

31. Phyllosilicates on Mars and implications for early martian climate.

Author

Poulet F, Bibring JP, Mustard JF, Gendrin A, Mangold N, Langevin Y, Arvidson RE, Gondet B, Gomez C, Berthé M, Erard S, Forni O, Manaud N, Poulleau G, Soufflot A, Combes M, Drossart P, Encrenaz T, Fouchet T, Melchiorri R, Bellucci G, Altieri F, Formisano V, Fonti S, Capaccioni F, Cerroni P, Coradini A, Korablev O, Kottsov V, Ignatiev N, Titov D, Zasova L, Pinet P, Schmitt B, Sotin C, Hauber E, Hoffmann H, Jaumann R, Keller U, and Forget F

Subjects
Clay, Hydrogen-Ion Concentration, Iron analysis, Magnesium analysis, Space Flight, Spacecraft, Sulfates analysis, Sulfates chemistry, Water analysis, Water chemistry, Aluminum Silicates analysis, Aluminum Silicates chemistry, Climate, Extraterrestrial Environment chemistry, Mars
Abstract

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected-phyllosilicates and sulphates--result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed.

Published
2005
Full Text
View/download PDF

32. EXOCAM: Mars in a box to simulate soil-atmosphere interactions.

Author

Rannou P, Chassefiere E, Encrenaz T, Erard S, Genin JM, Ingrin J, Jambon A, Jolivet JP, Raulin F, Renault P, Rochette P, Person A, Siguier JM, and Toublanc D

Subjects
Astronomy instrumentation, Equipment Design, Extraterrestrial Environment, Hydrogen Peroxide chemistry, Atmosphere chemistry, Exobiology instrumentation, Mars, Soil
Abstract

We present the principle of the EXOCAM chamber, devoted to the study of physical-chemical interactions between the atmosphere and the surface and subsurface in Mars conditions. The purpose of this experiment is to reach a better knowledge of the physical and chemical processes that altered the atmosphere-soil coupled system. We describe the scientific goals of EXOCAM, the multiple fields that will benefit from this experiment and the instrumentation that is devoted to the analysis of the results. We also give a description of the chamber and its main devices., (c2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.)

Published
2001
Full Text
View/download PDF

33. Minor constituents in the Martian atmosphere from the ISM/Phobos experiment.

Author

Rosenqvist J, Drossart P, Combes M, Encrenaz T, Lellouch E, Bibring JP, Erard S, Langevin Y, and Chassefiere E

Subjects
Astronomy instrumentation, Astronomy methods, Atmospheric Pressure, Dust, Models, Theoretical, Photochemistry, Spacecraft instrumentation, Spectrophotometry, Infrared methods, Sunlight, Temperature, Atmosphere analysis, Carbon Dioxide chemistry, Carbon Monoxide chemistry, Extraterrestrial Environment, Mars, Spectrophotometry, Infrared instrumentation, Water chemistry
Abstract

Global Martian atmospheric results derived from the infrared imaging spectrometer ISM flown aboard the Phobos 2 Soviet spacecraft are presented. Over low altitude regions the expected CO mixing ratio of (8 +/- 3) x 10(-4) is measured. Variations of the 2.35-micrometers feature are inconsistent with this value over the Great Martian Volcanoes. If the 2.35-micrometers band is entirely attributable to carbon monoxide, the CO mixing ratio is typically depleted by a factor of 3 over these high altitude areas. Orography should play a major role in the existence of this CO "hole." If, however, these spectral variations at 2.35 micrometers are due to the surface composition, the fraction of the surface covered by the responsible mineral must smoothly decrease as the surface elevation decreases. This phenomenon implies a strong interaction between the surface and the atmosphere for the Great Martian Volcanoes. Diurnal behavior and latitudinal variations of water vapor are globally consistent with Viking measurements. During the Phobos observations, the water vapor amounts over the bright equatorial regions range around 11 pr-micrometers during the day. These amounts are slightly larger than those inferred from 1976 to 1979. The lack of global dust storms during 1988-1989 could explain the enhancement of H2O in the atmosphere.

Published
1992
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results