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1. Revealing Callisto’s Carbon-rich Surface and CO2 Atmosphere with JWST

Author

Richard J. Cartwright, Geronimo L. Villanueva, Bryan J. Holler, Maria Camarca, Sara Faggi, Marc Neveu, Lorenz Roth, Ujjwal Raut, Christopher R. Glein, Julie C. Castillo-Rogez, Michael J. Malaska, Dominique Bockelée-Morvan, Tom A. Nordheim, Kevin P. Hand, Giovanni Strazzulla, Yvonne J. Pendleton, Katherine de Kleer, Chloe B. Beddingfield, Imke de Pater, Dale P. Cruikshank, and Silvia Protopapa

Subjects
Infrared spectroscopy, Galilean satellites, Callisto, James Webb Space Telescope, Natural satellite atmospheres, Natural satellite surfaces, Astronomy, QB1-991
Abstract

We analyzed spectral cubes of Callisto’s leading and trailing hemispheres, collected with the NIRSpec Integrated Field Unit (G395H) on the James Webb Space Telescope. These spatially resolved data show strong 4.25 μ m absorption bands resulting from solid-state ^12 CO _2 , with the strongest spectral features at low latitudes near the center of its trailing hemisphere, consistent with radiolytic production spurred by magnetospheric plasma interacting with native H _2 O mixed with carbonaceous compounds. We detected CO _2 rovibrational emission lines between 4.2 and 4.3 μ m over both hemispheres, confirming the global presence of CO _2 gas in Callisto’s tenuous atmosphere. These results represent the first detection of CO _2 gas over Callisto’s trailing side. The distribution of CO _2 gas is offset from the subsolar region on either hemisphere, suggesting that sputtering, radiolysis, and geologic processes help sustain Callisto’s atmosphere. We detected a 4.38 μ m absorption band that likely results from solid-state ^13 CO _2 . A prominent 4.57 μ m absorption band that might result from CN-bearing organics is present and significantly stronger on Callisto’s leading hemisphere, unlike ^12 CO _2 , suggesting these two spectral features are spatially antiassociated. The distribution of the 4.57 μ m band is more consistent with a native origin and/or accumulation of dust from Jupiter’s irregular satellites. Other, more subtle absorption features could result from CH-bearing organics, CO, carbonyl sulfide, and Na-bearing minerals. These results highlight the need for preparatory laboratory work and improved surface–atmosphere interaction models to better understand carbon chemistry on the icy Galilean moons before the arrival of NASA’s Europa Clipper and ESA’s JUICE spacecraft.

Published
2024
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2. Molecular Outgassing in Centaur 29P/Schwassmann–Wachmann 1 during Its Exceptional 2021 Outburst: Coordinated Multiwavelength Observations Using nFLASH at APEX and iSHELL at the NASA-IRTF

Author

Nathan X. Roth, Stefanie N. Milam, Michael A. DiSanti, Geronimo L. Villanueva, Sara Faggi, Boncho P. Bonev, Martin A. Cordiner, Anthony J. Remijan, Dominique Bockelée-Morvan, Nicolas Biver, Jacques Crovisier, Dariusz C. Lis, Steven B. Charnley, Emmanuel Jehin, Eva S. Wirström, and Adam J. McKay

Subjects
Molecular spectroscopy, High-resolution spectroscopy, Near-infrared astronomy, Radio astronomy, Comae, Comets, Astronomy, QB1-991
Abstract

The extraordinary 2021 September–October outburst of Centaur 29P/Schwassmann–Wachmann 1 afforded an opportunity to test the composition of primitive Kuiper disk material at high sensitivity. We conducted nearly simultaneous multiwavelength spectroscopic observations of 29P/Schwassmann–Wachmann 1 using iSHELL at the NASA Infrared Telescope Facility (IRTF) and nFLASH at the Atacama Pathfinder EXperiment (APEX) on 2021 October 6, with follow-up APEX/nFLASH observations on 2021 October 7 and 2022 April 3. This coordinated campaign between near-infrared and radio wavelengths enabled us to sample molecular emission from a wealth of coma molecules and to perform measurements that cannot be accomplished at either wavelength alone. We securely detected CO emission on all dates with both facilities, including velocity-resolved spectra of the CO ( J = 2–1) transition with APEX/nFLASH and multiple CO ( v = 1–0) rovibrational transitions with IRTF/iSHELL. We report rotational temperatures, coma kinematics, and production rates for CO and stringent (3 σ ) upper limits on abundance ratios relative to CO for CH _4 , C _2 H _6 , CH _3 OH, H _2 CO, CS, and OCS. Our upper limits for CS/CO and OCS/CO represent their first values in the literature for this Centaur. Upper limits for CH _4 , C _2 H _6 , CH _3 OH, and H _2 CO are the most stringent reported to date, and are most similar to values found in ultra CO-rich Oort cloud comet C/2016 R2 (PanSTARRS), which may have implications for how ices are preserved in cometary nuclei. We demonstrate the superb synergy of coordinated radio and near-infrared measurements, and advocate for future small-body studies that jointly leverage the capabilities of each wavelength.

Published
2023
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3. Volatile Abundances, Extended Coma Sources, and Nucleus Ice Associations in Comet C/2014 Q2 (Lovejoy)

Author

Neil Dello Russo, Ronald J. Vervack, Jr, Hideyo Kawakita, Boncho P. Bonev, Michael A. Disanti, Erika L. Gibb, Adam J. McKay, Anita L. Cochran, Harold A. Weaver, Nicolas Biver, Jacques Crovisier, Dominique Bockelée-Morvan, Hitomi Kobayashi, Walter M. Harris, Nathaniel X. Roth, Mohammad Saki, and Younas Khan

Subjects
Astronomy
Abstract

High-resolution infrared spectra of comet C/2014 Q2 Lovejoy were acquired with NIRSPEC at the W. M. Keck Observatory on two post-perihelion dates(UT 2015 February 2 and 3).H2O was measured simultaneously with CO,CH3OH, H2CO, CH4, C2H6,C2H4, C2H2, HCN, and NH3 on both dates, and rotational temperatures, production rates, relative abundances, H2O ortho-to-para ratios, and spatial distributions in the coma were determined. The first detection of C2H4in a comet from ground-based observations is reported. Abundances relative to H2O for all species were found to be in the typical range compared with values for other comets in the overall population to date. There is evidence of variability in rotational temperatures and production rates on timescales that are small compared with the rotational period of the comet. Spatial distributions of volatiles in the coma suggest complex outgassing behavior.CH3OH, HCN, C2H6, and CH4 spatial distributions in the coma are consistent with direct release from associated ices in the nucleus and are peaked in a more sunward direction compared with co-measured dust. H2O spatial profiles are clearly distinct from these other four species, likely due to a sizable coma contribution from icy grain sublimation.Spatial distributions for C2H2,H2CO, and NH3suggest substantial contributions from extended coma sources, providing further evidence for distinct origins and associations for these species in comets. CO shows a different spatial distribution compared with other volatiles, consistent with jet activity from discrete nucleus ice sources.

Published
2022
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4. Leveraging the Atacama Compact Array for Cometary Science: An Interferometric Survey of Comet C/2015 ER61 (PanSTARRS) and Evidence for a Distributed Source of Carbon Monosulfide

Author

Nathaniel X Roth, Stefanie N Milam, Martin A Cordiner, Dominique Bockelée-Morvan, Nicolas Biver, Jérémie Boissier, Dariusz C Lis, Anthony J. Remijan, and Steven B Charnley

Subjects
Astronomy, Lunar And Planetary Science And Exploration
Abstract

We report the first survey of molecular emission from cometary volatiles using standalone Atacama Compact Array (ACA) observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2015 ER61 (PanSTARRS) carried out on UT 2017 April 11 and 15, shortly after its April 4 outburst. These measurements of HCN, CS, CH3OH, H2CO, and HNC (along with continuum emission from dust) probed the inner coma of C/2015 ER61, revealing asymmetric outgassing and discerning parent from daughter/distributed source species. This work presents spectrally integrated flux maps, autocorrelation spectra, production rates, and parent scale lengths for each molecule and a stringent upper limit for CO. HCN is consistent with direct nucleus release in C/2015 ER61, whereas CS, H2CO, HNC, and potentially CH3OH are associated with distributed sources in the coma. Adopt- ing a Haser model, parent scale lengths determined for H2CO (Lp ∼ 2200 km) and HNC (Lp ∼ 3300 km) are consistent with previous work in comets, whereas significant extended source production (Lp ∼ 2000 km) is indicated for CS, suggesting production from an unknown parent in the coma. The continuum presents a point-source distribution with a flux density implying an excessively large nucleus, inconsistent with other estimates of the nucleus size. It is best explained by the thermal emission of slowly moving outburst ejectas, with total mass 5–8 × 1010 kg. These results demonstrate the power of the ACA for revealing the abundances, spatial distributions, and locations of molecular production for volatiles in moderately bright comets such as C/2015 ER61.

Published
2021
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7. Analysis of Gas–Dust Outbursts Observed at 67P/Churyumov–Gerasimenko

Author

Giovanna Rinaldi, John W. Noonan, Dominique Bockelée-Morvan, Andrea Longobardo, Alessandra Migliorini, Mauro Ciarniello, Andrea Raponi, Gianrico Filacchione, and Fabrizio Capaccioni

Abstract

Cometary outbursts are well-known and offer a valuable window into the composition of comet nuclei with their forceful ejection of dust and gas that reveals interior components of the comet. Understanding how different types of outbursts influence the observed dust properties and volatile abundances is necessary to better interpret what signatures can be attributed to primordial composition and what features are the result of processing. As such, it is an important task best undertaken with a multi-instrument approach. During the period between July and November 2015, the Rosetta spacecraft had monitored the inner coma of comet 67P/Churyumov-Gerasimenko (67P/CG). This period encompassed the passage at perihelion (August 2015) resulting in the most active part of its orbit. The Visible InfraRed the Thermal Imaging Spectrometer (VIRTIS) [1] and the ALICE ultraviolet spectrograph, [2] onboard Rosetta observed and detected a series of transient events associated with outburst [Fig. 1]. Previous Alice observations of outbursts have revealed a range of compositions and emission processes within these periods of increased activity. H2O, CO2, CO, and O2 were all indirectly observed within outbursts via emission from the daughter products H, C, and O, identified in the spectra as the first three members of the H I Lyman series, O I multiplets at 1152, 1304, and 1356 Å, and weak multiplets of C I at 1561 and 1657 Å [3]. VIRTIS detected and characterized the dust properties of the outburst in terms of light curve, color, and dust mass loss in the VIS and IR wavelength range. The aim of this work is to take advantage of the capabilities of two instruments to analyze the dust and gas coma trends during these transient events in the perihelion and post-perihelion period. Alice and VIRTIS observe two outbursts on November 7, 2015, displaying both gas and dust components. The gas components show different gas emission characteristics. The outburst B was approximately twice as strong, with respect to the outburst A [Fig. 2], based on the intensity of atomic emissions, which is inverse of the VIRTIS-M measured dust radiances. VIRTIS-M observations of the dust component show that outburst A had a maximum radiance larger than outburst B [Fig. 3]. Alice outburst spectra show the transient events characterized by a different CO2/H2O and O2/H2O ratio as determined from spectral modeling and different ob-served O I 1356/O I 1304 Å ratio. In cases where dissociative electron impact excitation on O2 or CO2 is dominant, we would expect the O I 1356/O I 1304 Å ratio greaten than 1, while if dissociative electron impact occurs on H2O, this value would be less than 1 [5, 10]. Outburst B contained more CO2 and O2, while outburst A was relatively richer in H2O. Elevated CO2 content could indicate a more pristine surface origin (i.e., fracture deepening) and the subsequent activity was sustained for over two hours. The outbursts are characterised by a sudden increase of the dust radiance continuum, fol-lowed by a gentle decrease lasting a few minutes to tens of minutes. The VIRTIS observations show two kind of outbursts. The first type is characterize by a strong color gradient values in the dust continuum with respect to the surrounding coma and the second type doesn’t show colour difference [4,5,7]. The outburst colour sequence in the VIS and IR show a colour gradient pattern which seems correlated to the intensity of the dust radiance within the outburst [7,8]. The first type of outburst shows a VIS colour behaviour reaching the bluer values of 6±1.4 % /100 nm and returning to the pre-outburst value of about 14 % /100 nm [4,5]. The IR continuum emission is also characterised by high colour temperatures of about 600 K and a bolometric albedo of 0.6 [5]. Colour temperatures of 600 K thus reveals the presence of very small grains (less than 100 nm) in the outburst material. The bright grains in the ejecta could be silicate grains, implying the thermal degradation of the carbonaceous material, or icy grains. The rapid increase in radiance at the start of an outburst event is not due primarily to an increase in the number of existing dust particles, but rather to the release of small and bright silicate or icy particles with a high geometric albedo and a filling factor between 1.3 and 5.0 % [4,5]. For the second type of outburst, we found no clear evidence of different reddening values in the dust continuum with respect to the surrounding coma. The reason is probably that this is a faint outburst and the signal from the background coma dominates, so the colour of the outburst is not measurable. The VIS dust color is around 13.1% /100 nm [4,5,7]. Nearly 30 new outbursts observed by VIRTIS have been identified and have corresponding Alice UV spectra. Following the successful characterization of the 7 November outbursts we will apply the same methodology to the full pre/post-perihelion sample. By increasing the sample size by a factor of nearly 15 we will be able to more rigorously understand the link between gas intensity and outburst composition and explore the correlation between dust colour and outburst strength. References: [1] Coradini, A. et al. (2007), SSR 128, 1-4, 529-555; [2] Stern, S. A., Slater, D., Scherrer, J., et al. 2007, SSRv, 128, 507; [3] Feldman, P. D., A’Hearn, M. F., Feaga, L. M., et al. 2016, ApJL, 825, L8.[4] Bockelee-Morvan D., et al., 2017, MNRAS, 469, S443; [5] Rinaldi, G., Bockelée-Morvan, D., Ciarniello, M., et al. 2018, MNRAS, 481, 1235; [6] Fornasier, S., Hoang, V. H., Hasselmann, P. H., et al. 2019b, A&A, 630, A7; [7] Noonan, J. G., Rinaldi, S. A., Feldman, P. D., et al. 2021, AJ, 162, 4

Published
2022

8. The 3.1 μm absorption feature on asteroids (24) Themis and (65) Cybele is not due to surface water ice

Author

Laurence O'Rourke, Thomas G. Müller, Nicolas Biver, Dominique Bockelée-Morvan, Sunao Hasegawa, Ivan Valtchanov, Michael Küppers, Sonia Fornasier, Humberto Campins, Hideaki Fujiwara, David Teyessier, and Tanya Lim

Abstract

Previous research on Asteroids (24) Themis and (65) Cybele have shown the presence of an absorption feature at 3.1 μm reported to be directly linked to surface water ice. We searched for water vapor escaping from these asteroids with the Herschel Space Observatory HIFI (Heterodyne Instrument for the Far Infrared) Instrument. While no H2O line emission was detected, we obtained sensitive 3σ water production rate upper limits of Q(H2O)< 4.1×1026 molecules s−1 for Themis and Q(H2O) 26 molecules s−1 for the case of Cybele. Using a thermophysical model, we merged data from the Subaru/Cooled Mid-Infrared Camera and Spectrometer and the Herschel SPIRE (Spectral and Photometric Imaging Receiver) instrument with the contents of a multi-observatory database and thus derived new radiometric properties for these two asteroids. For Themis, we obtained a thermal inertia G = 20 +25-10 J m−2 s−1/2 K−1, a diameter 192 +10-7 km, and a geometric V-band albedo pV=0.07±0.01. For Cybele, we found a thermal inertia G = 25+28-19 J m−2 s−1/2 K−1, a diameter 282±9 km, and an albedo pV=0.042±0.005. Using all inputs, we estimated that water ice intimately mixed with the asteroids’ dark surface material would cover

Published
2021

9. AMBITION – comet nucleus cryogenic sample return

Author

Hervé Cottin, Carsten Güttler, Stavro Ivanoski, Colin Snodgrass, Claudio Codella, Jean-Baptiste Vincent, Kelly E. Miller, Pierre Henri, Maria Drozdovskaya, Alain Herique, Gianrico Filacchione, Kathrin Altwegg, Nicolas Thomas, Martin Bizzarro, Maria Cristina De Sanctis, Rosita Kokotanekova, E. Bianchi, Björn Davidsson, Lydie Bonal, Stefan Ulamec, Cécile Engrand, Cecilia Tubiana, Dominique Bockelée-Morvan, Mathieu Choukroun, Anny Chantal Levasseur-Regourd, Marina Galand, Alessandra Rotundi, Jürgen Blum, M. Schönbächler, Fabrizio Capaccioni, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Centre for Star and Planet Formation (STARPLAN), Globe Institute, Faculty of Health and Medical Sciences, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Health and Medical Sciences, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Natural History Museum of Denmark, Faculty of Science [Copenhagen], Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astrofisico di Arcetri (OAA), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Center for Space and Habitability (CSH), University of Bern, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Imperial College London], Imperial College London, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), European Southern Observatory (ESO), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Southwest Research Institute [San Antonio] (SwRI), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, German Aerospace Center (DLR), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Universität Bern [Bern], Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Health and Medical Sciences, University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Paris (UP)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Université Nice Sophia Antipolis (... - 2019) (UNS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universita degli studi di Napoli 'Parthenope' [Napoli], Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Space and Atmospheric Physics Group [London], Blackett Laboratory, and Imperial College London-Imperial College London

Subjects
Solar System, 010504 meteorology & atmospheric sciences, Comet, Context (language use), 01 natural sciences, Space missions, Space exploration, Astrobiology, Comet nucleus, 0103 physical sciences, Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Solar system, 520 Astronomy, Giant planet, Astronomy and Astrophysics, 620 Engineering, 13. Climate action, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], Formation and evolution of the Solar System, Geology
Abstract

We describe the AMBITION project, a mission to return the first-ever cryogenically-stored sample of a cometary nucleus, that has been proposed for the ESA Science Programme Voyage 2050. Comets are the leftover building blocks of giant planet cores and other planetary bodies, and fingerprints of Solar System’s formation processes. We summarise some of the most important questions still open in cometary science and Solar System formation after the successful Rosetta mission. We show that many of these scientific questions require sample analysis using techniques that are only possible in laboratories on Earth. We summarize measurements, instrumentation and mission scenarios that can address these questions. We emphasize the need for returning a sample collected at depth or, still more challenging, at cryogenic temperatures while preserving the stratigraphy of the comet nucleus surface layers. We provide requirements for the next generation of landers, for cryogenic sample acquisition and storage during the return to Earth. Rendezvous missions to the main belt comets and Centaurs, expanding our knowledge by exploring new classes of comets, are also discussed. The AMBITION project is discussed in the international context of comet and asteroid space exploration.

Published
2021

10. Investigation into the disparate origin of CO2 and H2O outgassing for Comet 67/P

Author

Giovanna Rinaldi, Nicolas Fougere, Michael R. Combi, Maria Teresa Capria, Maria Cristina De Sanctis, Lyn R. Doose, Stéphane Erard, André Bieler, Fabrizio Capaccioni, Jacques Crovisier, Dominique Bockelée-Morvan, C. Leyrat, Gianrico Filacchione, Uwe Fink, M. I. Blecka, Fredric W. Taylor, Alessandra Migliorini, Giuseppe Piccioni, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), 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), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and POL

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Vapor pressure, Comet, Imaging spectrometer, Astronomy and Astrophysics, Coma (optics), Astrophysics, 01 natural sciences, Outgassing, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Mixing ratio, Annulus (firestop), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Intensity (heat transfer), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present an investigation of the emission intensity of CO2and H2O and their distribution in the coma of 67P/ Churyumov–Gerasimenko obtained by the VIRTIS-M imaging spectrometer on the Rosetta mission. We analyze 4 data cubes from Feb. 28, and 7 data cubes from April 27, 2015. For both data sets the spacecraft was at a sufficiently large distance from the comet to allow images of the whole nucleus and the surrounding coma. We find that unlike water which has a reasonably predictable behavior and correlates well with the solar illumination, CO2outgasses mostly in local regions or spots. Furthermore for the data on April 27, the CO2evolves almost exclusively from the southern hemisphere, a region of the comet that has not received solar illumination since the comet's last perihelion passage. Because CO2and H2O have such disparate origins, deriving mixing ratios from local column density measurements cannot provide a meaningful measurement of the CO2/H2O ratio in the coma of the comet. We obtain total production rates of H2O and CO2by integrating the band intensity in an annulus surrounding the nucleus and obtain pro-forma production rate CO2/H2O mixing ratios of ∼5.0% and ∼2.5% for Feb. 28 and April 27, respectively. Because of the highly variable nature of the CO2evolution from the surface we do not believe that these numbers are diagnostic of the comet's bulk CO2/H2O composition. We believe that our investigation provides an explanation for the large observed variations reported in the literature for the CO2/H2O production rate ratios. Our mixing ratio maps indicate that, besides the difference in vapor pressure of the two gases, this ratio depends on the comet's rotational orientation combined with its complex geometric shape which can result in quite variable rates of erosion for different surface areas such as the northern and southern hemisphere. Our annulus measurement for the total water production for Feb. 28 at 2.21AU from the Sun is 2.5×1026molecules/s while for April 27 at 1.76 AU it is 4.65×1026. We find that about 83% of the H2O resides in the illuminated portion of our annulus and about 17% on the night side. We also make an attempt to obtain the fraction of the H2O production coming from the highly active neck of the comet versus the rest of the illuminated surface from the pole-on view of Feb. 28 and estimate that about 60% of the H2O derives from the neck area. A rough estimate of the water surface evaporation rate of the illuminated nucleus for April 27 yields about 5×1019molecules/s/m2. Spatial radial profiles of H2O on April 27 on the illuminated side of the comet, extending from 1.78 to 6.47km from the nucleus center, show that water follows model predictions quite well, with the gas accelerating as it expands into the coma. Our dayside radial profile allows us to make an empirical determination of the expansion velocity of water. On the night side the spatial profile of water follows 1/ρ. The CO2profiles do not exhibit any acceleration into the coma but are closely matched by a 1/ρprofile.

Published
2021

11. Cometary coma dust size distribution from in situ IR spectra

Author

Stefano Mottola, Giovanna Rinaldi, Stéphane Erard, Marco Fulle, Andrea Longobardo, M. Salatti, Maria Teresa Capria, Fredric W. Taylor, Alessandra Rotundi, Stavro Ivanovski, Dominique Bockelée-Morvan, G. P. Tozzi, Ernesto Palomba, Mauro Ciarniello, V. Della Corte, Gianrico Filacchione, C. Leyrat, Fabrizio Capaccioni, Emiliano D'Aversa, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), INAF - Osservatorio Astronomico di Capodimonte (OAC), 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), INAF - Osservatorio Astrofisico di Arcetri (OAA), DLR Institute of Planetary Research, and German Aerospace Center (DLR)

Subjects
[PHYS]Physics [physics], In situ, Physics, 010504 meteorology & atmospheric sciences, Distribution (number theory), comets: individual: 67P/Churyumov-Gerasimenko, Infrared spectroscopy, Astronomy, Astronomy and Astrophysics, Coma (optics), Astrophysics, methods: data analysis, 01 natural sciences, Methods observational, techniques: imaging spectroscopy, 13. Climate action, Space and Planetary Science, 0103 physical sciences, comets: individual: 67P/Churyumov-Gerasimenko, methods: data analysis, methods: observational, space vehicles: instruments, techniques: imaging spectroscopy, methods: observational, space vehicles: instruments, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Dust is the most abundant component in cometary comae. Here, we investigate the dust size distribution in 67P/Churyumov-Gerasimenko (67P/CG) using data from the Rosetta spacecraft that was in close proximity to the comet from 2014 August to 2016 September. The Visual, Infrared and Thermal Imaging Spectrometer (VIRTIS-M), spectral range of 0.25–5 μm, and the Grain Impact Analyser and Dust Accumulator (GIADA), both part of the Rosetta payload, together provide a powerful means to characterize the dust coma properties. On March 28, Rosetta performed a flyby close to the nucleus that allowed GIADA to detect a large amount of dust particles used to constraint the differential size distribution power-law index of −2.2 ± 0.3. In April 2015, VIRTIS-M observed the spectral radiance in the wavelength range of 1–5 μm. A simple radiative transfer model has been applied to simulate the VIRTIS-M radiances, thus allowing to infer the dust properties. We assumed an optically thin dust coma and spherical amorphous carbon particles in the size range between 0.1 to 1000 μm. We obtained the infrared data best fit with a differential dust size distribution power-law index of −3.1 . This index matches the one determined using GIADA March 2015 data indicating that, before perihelion, the inner coma radiance is dominated by particles larger than 10 μm; and the dust coma did not change its properties during most of the 67P/CG inbound orbit. + 3 − 0.1

Published
2021

12. Isotopic Ratios in Water and the Origin of Earth’s Oceans

Author

Dariusz C. Lis, Dominique Bockelée-Morvan, Klaus M. Pontoppidan, Martin A. Cordiner, Miguel de Val-Borro, Karin I. Öberg, Geoffrey A. Blake, Stefanie N. Milam, Nicolas Biver, Julie Castillo-Rogez, Karen J. Meech, Paul F. Goldsmith, Imran Mehdi, Youngmin Seo, Steven B. Charnley, Imke de Pater, Quentin Kral, Mark Gurwell, and Edwin A. Bergin

Subjects
Geology, Earth (classical element), Astrobiology
Published
2021

13. Subsurface properties and early activity of comet 67P/Churyumov-Gerasimenko

Author

Samuel Gulkis, Mark Allen, Paul von Allmen, Gerard Beaudin, Nicolas Biver, Dominique Bockelée-Morvan, Mathieu Choukroun, Jacques Crovisier, Björn J. R. Davidsson, Pierre Encrenaz, Therese Encrenaz, Margaret Frerking, Paul Hartogh, Mark Hofstadter, Wing-Huen Ip, Michael Janssen, Christopher Jarchow, Stephen Keihm, Seungwon Lee, Emmanuel Lellouch, Cedric Leyrat, Ladislav Rezac, F. Peter Schloerb, and Thomas Spilker

Published
2015
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14. A molecular wind blows out of the Kuiper belt

Author

Amy Bonsor, Luca Matrà, Mark C. Wyatt, Quentin Kral, A. Guilbert-Lepoutre, Dominique Bockelée-Morvan, Emmanuel Lellouch, F. Le Petit, N. Biver, J. E. Pringle, Julianne I. Moses, G. Randall Gladstone, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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 d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Southwest Research Institute [San Antonio] (SwRI)

Subjects
Solar System, Comet, Interplanetary medium, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, circumstellar matter, Astrobiology, Atmosphere, Physics - Space Physics, 0103 physical sciences, Sun: heliosphere, 010303 astronomy & astrophysics, planetary systems, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Astronomy and Astrophysics, Planetary system, Space Physics (physics.space-ph), Solar wind, solar wind, 13. Climate action, Space and Planetary Science, Kuiper belt: general, interplanetary medium, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Heliosphere, Astrophysics - Earth and Planetary Astrophysics
Abstract

Gas has been detected in many exoplanetary systems ($>$10 Myr), thought to be released in the destruction of volatile-rich planetesimals orbiting in exo-Kuiper belts. In this letter, we aim to explore whether gas is also expected in the Kuiper belt (KB) in our Solar System. To quantify the gas release in our Solar System, we use models for gas release that have been applied to extrasolar planetary systems, as well as a physical model that accounts for gas released due to the progressive internal warming of large planetesimals. We find that only bodies larger than about 4 km can still contain CO ice after 4.6 Gyr of evolution. This finding may provide a clue as to why Jupiter-family comets, thought to originate in the Kuiper belt, are deficient in CO compared to Oort-clouds comets. We predict that gas is still produced in the KB right now at a rate of $2 \times 10^{-8}$ M$_\oplus$/Myr for CO and orders of magnitude more when the Sun was younger. Once released, the gas is quickly pushed out by the Solar wind. Therefore, we predict a gas wind in our Solar System starting at the KB location and extending far beyond with regards to the heliosphere with a current total CO mass of $\sim 2 \times 10^{-12}$ M$_\oplus$. We also predict the existence of a slightly more massive atomic gas wind made of carbon and oxygen (neutral and ionized) with a mass of $\sim 10^{-11}$ M$_\oplus$. We predict that gas is currently present in our Solar System beyond the Kuiper belt and that although it cannot be detected with current instrumentation, it could be observed in the future with an in situ mission using an instrument similar to Alice on New Horizons with larger detectors. Our model of gas release due to slow heating may also work for exoplanetary systems and provide the first real physical mechanism for the gas observations., accepted for publication as a Letter to the editor in A&A; abstract shortened; 15 pages, 5 figures, 4 tables

Published
2021
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15. Leveraging the ALMA Atacama Compact Array for Cometary Science: An Interferometric Survey of Comet C/2015 ER61 (PanSTARRS) and Evidence for a Distributed Source of Carbon Monosulfide

Author

Nathan Roth, Nicolas Biver, Stefanie N. Milam, Steven B. Charnley, Jérémie Boissier, Dominique Bockelée-Morvan, Dariusz C. Lis, Martin A. Cordiner, and Anthony J. Remijan

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Continuum (design consultancy), Comet, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, Submillimeter Array, Spectral line, chemistry.chemical_compound, chemistry, Space and Planetary Science, Carbon monosulfide, Millimeter, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the first survey of molecular emission from cometary volatiles using standalone Atacama Compact Array (ACA) observations of the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2015 ER61 (PanSTARRS) carried out on UT 2017 April 11 and 15, shortly after its April 4 outburst. These measurements of HCN, CS, CH$_3$OH, H$_2$CO, and HNC (along with continuum emission from dust) probed the inner coma of C/2015 ER61, revealing asymmetric outgassing and discerning parent from daughter/distributed source species. This work presents spectrally integrated flux maps, autocorrelation spectra, production rates, and parent scale lengths for each molecule, and a stringent upper limit for CO. HCN is consistent with direct nucleus release in C/2015 ER61, whereas CS, H$_2$CO, HNC, and potentially CH$_3$OH are associated with distributed sources in the coma. Adopting a Haser model, parent scale lengths determined for H$_2$CO (L$_p$ $\sim$ 2200 km) and HNC (L$_p$ $\sim$ 3300 km) are consistent with previous work in comets, whereas significant extended source production (L$_p$ $\sim$ 2000 km) is indicated for CS, suggesting production from an unknown parent in the coma. The continuum presents a point-source distribution, with a flux density implying an excessively large nucleus, inconsistent with other estimates of the nucleus size. It is best explained by the thermal emission of slowly-moving outburst ejectas, with total mass 5--8 $\times$ 10$^{10}$ kg. These results demonstrate the power of the ACA for revealing the abundances, spatial distributions, and locations of molecular production for volatiles in moderately bright comets such as C/2015 ER61.

Published
2021
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16. AMBITION, the Comet Nucleus Cryogenic Sample Return mission for ESA Voyage 2050 program

Author

Gianrico Filacchione and Dominique Bockelée-Morvan

Subjects
Engineering, Sample return mission, business.industry, Comet nucleus, Astronomy, business
Abstract

Since the 1980s, ESA has played a leading role in cometary space science with Giotto and the Rosetta/Philae missions to comets 1P/Halley and 67P/Churyumov-Gerasimenko, respectively. These missions have greatly improved our knowledge of comets and placed Europe in an ideal position for the preparation of future cometary missions. After a cometary flyby mission (Giotto) and an orbiter (Rosetta) with a nucleus lander (Philae), and the selection of F-class Comet Interceptor ESA mission, the next major step in cometary science would be a cryogenic sample return mission as studied in the AMBITION proposal [1] which was submitted to ESA in the context of the future Voyage 2050 program. Despite the success of previous missions, a number of high priority scientific questions are still debated within the cometary community: How did cometary materials assemble? What are the building blocks of cometary nuclei? Which post-planetesimal evolutionary paths need to be considered? Are comets collisional fragments or primordial planetesimals? Which cometary components originate from the time before the formation of the Solar System? What is the nature of the refractory organic materials? How and where did these components form? Are there differences in physical/chemical properties in the comet populations? What are the commonalities and differences between comets and primitive asteroids? Are these distinct populations? Do comets, Main Belt comets and active asteroids have different primordial reservoirs? How does comet activity work? How do surface and coma observations reconnect with the pristine, deep interior? How are the dusty coma, the surrounding plasma, and the nucleus interacting together? Do interactions with the solar wind influence the activity and evolution of comets? What contributions did comets make to reservoirs of volatiles and prebiotic compounds on early Earth? The best approach to answer these questions is to return a pristine and volatile rich cometary sample to Earth. Such a sample, preserved at cryogenic temperature, will be transferred to a state-of-the-art curation facility, where it will be investigated in great detail. In this scenario part of the sample will be studied by means of different analytical techniques in laboratory-controlled conditions while the remaining sample will be stored at cryogenic temperature for future investigations. Laboratory analyses of the returned sample can achieve much higher precision and resolution measurements as compared to in-situ measurements. The AMBITION study has considered different mission targets (see Figure 1), including Centaurs, Jupiter family comets and its extinct members, returning Oort cloud comets, dynamically new comets, main belt comets and interstellar comets as possible candidates. Among them, Jupiter family comets are the ones which offer the best characteristics, in terms of orbital parameters, evolutionary history, composition and activity, to be to be selected for an L-class cryogenic sample return mission. The other targets could be explored by more consolidated (orbiters, landers) small and medium class missions. The selection, collection and storage of the sample at controlled cryogenic temperature and pressure during the return flight, Earth re-entry and landing phases will require significant technological advancement to guarantee maintenance of the optimal environmental conditions for the collected sample. Several options are identified for pristine sample collection from the cometary nucleus, including subsurface corers able to extract carrots up to 3 m depth as well as grabbers and manipulator arms to collect ice-rich, semi-buried boulders from the surface. The AMBITION mission is the “Holy Grail” in the field of cometary exploration and Solar System formation. For its implementation it will need a strong commitment from the scientific community, industrial partners, ESA and national space agencies. Figure 1: Approximate mission classes for different mission and comet types, in increasing complexity from left to right, and covering varying evolution stages of comets from the four possible reservoirs (Kuiper Belt, the Oort cloud, the Main Belt, and other planetary systems). Shading indicates approximate cost from yellow (F-class) through orange (M-class) to red (L-class or multiagency flagship missions). Hatched boxes indicate that such a combination is unfeasible, mostly due to excessive ∆v requirements. Past and planned missions are shown. From [1]. [1] Bockelée-Morvan, D. et al., AMBITION, Comet Nucleus Cryogenic Sample Return (2019), eprint, 2019arXiv190711081B

Published
2020

17. Low Water Outgassing from (24) Themis and (65) Cybele: 3.1 μ m Near-IR Spectral Implications

Author

T. G. Müller, Michael Küppers, D. Teyssier, I. Valtchanov, N. Biver, Hideaki Fujiwara, T. L. Lim, Sonia Fornasier, Dominique Bockelée-Morvan, Laurence O'Rourke, Humberto Campins, Sunao Hasegawa, Agence Spatiale Européenne (ESA), European Space Agency (ESA), Max-Planck-Institut für Extraterrestrische Physik (MPE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), European Space Astronomy Centre (ESAC), University of Central Florida [Orlando] (UCF), Faculty of Science and Technology [Tokyo], Seikei University, 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), AUTRES, and Dept. of Physics

Subjects
010504 meteorology & atmospheric sciences, Thermal inertia, Main belt asteroids, Main-belt comets, Astrophysics, 01 natural sciences, symbols.namesake, Far infrared, Bond albedo, 0103 physical sciences, Comets, 010303 astronomy & astrophysics, Astronomy data modeling, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrometer, Astronomy and Astrophysics, Small solar system bodies, Space observatory, Asteroids, Outgassing, 13. Climate action, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], symbols, Water vapor
Abstract

International audience; Asteroids (24) Themis and (65) Cybele have an absorption feature at 3.1 μm reported to be directly linked to surface water ice. We searched for water vapor escaping from these asteroids with the Herschel Space Observatory Heterodyne Instrument for the Far Infrared. While no H 2 O line emission was detected, we obtain sensitive 3σ water production rate upper limits of Q(H 2 O)

Published
2020

18. Dust-to-Gas and Refractory-to-Ice Mass Ratios of Comet 67P/Churyumov-Gerasimenko from Rosetta Observations

Author

Ekkehard Kührt, Nicolas Biver, Dominique Bockelée-Morvan, Raphael Marschall, Mathieu Choukroun, Matthew Taylor, Nicolas Thomas, Kathrin Altwegg, Martin Hilchenbach, Martin Pätzold, Alain Herique, Joanna Drążkowska, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Physikalisches Institut [Bern], Universität Bern [Bern], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Ludwig Maximilian University of Munich [Germany] (LMU München), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Rhenish Institute for Environmental Research (RIU), University of Cologne, RSSD of ESA, ESTEC, Noordwijk, The Netherlands, and Physics Institute, University of Bern, 3012 Bern, Switzerland

Subjects
Physics, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, refractory-to-ice ratio, Comet, Astronomy and Astrophysics, Astrophysics, Mass ratio, 620 Engineering, 01 natural sciences, Planetary science, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Rosetta, Comets, Refractory-to-Ice mass ratio, Single point, Dust-to-gas ratio, 010303 astronomy & astrophysics, Institut für Optische Sensorsysteme, Refractory (planetary science), 0105 earth and related environmental sciences
Abstract

This chapter reviews the estimates of the dust-to-gas and refractory-to-ice mass ratios derived fromRosettameasurements in the lost materials and the nucleus of 67P/Churyumov-Gerasimenko, respectively. First, the measurements byRosettainstruments are described, as well as relevant characteristics of 67P. The complex picture of the activity of 67P, with its extreme North-South seasonal asymmetry, is presented. Individual estimates of the dust-to-gas and refractory-to-ice mass ratios are then presented and compared, showing wide ranges of plausible values.Rosetta’s wealth of information suggests that estimates of the dust-to-gas mass ratio made in cometary comae at a single point in time may not be fully representative of the refractory-to-ice mass ratio within the cometary nuclei being observed.

Published
2020

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

Author

Gabriele Arnold, Vassilissa Vinogradoff, Andrea Raponi, Lydie Bonal, Eric Quirico, Antoine Pommerol, Dominique Bockelée-Morvan, Gianrico Filacchione, Vito Mennella, S. Potin, P. Beck, Federico Tosi, L. Moroz, Olivier Poch, Alexandre Faure, Batiste Rousseau, Nicolas Thomas, L. Flandinet, Bernard Schmitt, F. Mancarella, M. C. De Sanctis, Stéphane Erard, P. Hily-Blant, Ernesto Palomba, Istiqomah Istiqomah, Mauro Ciarniello, Andrea Longobardo, O. Brissaud, Patrice Theulé, David Kappel, C. Leyrat, Fabrizio Capaccioni, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), ANR-17-CE31-0004,CLASSY,Composition des surfaces du Système Solaire de bas albédo(2017), European Project: ERC-CoG2017-771691,SOLARYS, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), and 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)

Subjects
animal structures, 010504 meteorology & atmospheric sciences, Interstellar cloud, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, complex mixtures, Astrobiology, chemistry.chemical_compound, 0103 physical sciences, Ammonium, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Refractory (planetary science), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, 520 Astronomy, food and beverages, 620 Engineering, Nitrogen, chemistry, 13. Climate action, Asteroid, Absorption band, sense organs, biological phenomena, cell phenomena, and immunity, Astrophysics - Earth and Planetary Astrophysics
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., Comment: Main manuscript and Supplementary material document, Accepted for publication in Science on February 14, 2020

Published
2020

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

Author

Vito Mennella, Giovanna Rinaldi, Maria Cristina De Sanctis, Gabriele Arnold, Stéphane Erard, Michelangelo Formisano, Mauro Ciarniello, Andrea Longobardo, Fabrizio Capaccioni, Stefano Mottola, Dominique Bockelée-Morvan, Gianrico Filacchione, Andrea Raponi, Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), ITA, FRA, and DEU

Subjects
67P/Churyumov-Gerasimenko, Multidisciplinary, Materials science, 010504 meteorology & atmospheric sciences, Astrophysics, sublimation, 01 natural sciences, Grain size, Bluing, Amorphous carbon, 13. Climate action, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Particle-size distribution, Sublimation (phase transition), Water ice, Surface layer, comets, Scattered light, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Solar heating of a cometary surface provides the energy necessary to sustain gaseous activity, through which dust is removed1,2. In this dynamical environment, both the coma3,4 and the nucleus5,6 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 shapes7, lifted and diffused by gases freed from the sublimation of surface ices8,9. The visible colour of dust particles is highly variable: carbonaceous organic material-rich grains10 appear red while magnesium silicate-rich11,12 and water-ice-rich13,14 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–Bopp15 or in the fragmented grains in the coma16 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 117. 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 passage18. 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. Spectral analysis of the VIRTIS dataset shows two opposite seasonal colour cycles in the coma and on the surface of comet 67P/Churyumov–Gerasimenko, indicating an orbital water-ice cycle.

Published
2020

21. Probing the Evolutionary History of Comets: An Investigation of the Hypervolatiles CO, CH4, and C2H6 in the Jupiter-family Comet 21P/Giacobini-Zinner

Author

Nicolas Fougere, Michael A. DiSanti, Adam J. McKay, Erika L. Gibb, Dominique Bockelée-Morvan, Neil Dello Russo, Nicolas Biver, Hideyo Kawakita, Ronald J. Vervack, Mohammad Saki, Boncho P. Bonev, Lori M. Feaga, Yinsi Shou, Anita L. Cochran, Michael R. Combi, Nathan Roth, NASA Goddard Space Flight Center (GSFC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Comet, Infrared telescope, Astronomy and Astrophysics, Context (language use), Molecular spectroscopy, 01 natural sciences, Astrobiology, Molecular spectroscopy (2095), Jupiter, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Near infrared astronomy (1093), High resolution spectroscopy (2096)
Abstract

International audience; Understanding the cosmogonic record encoded in the parent volatiles stored in cometary nuclei requires investigating whether evolution (thermal or otherwise) has modified the composition of short-period comets during successive perihelion passages. As the most volatile molecules systematically observed in comets, the abundances of CO, CH 4 , and C 2 H 6 in short-period comets may serve to elucidate the interplay between natal conditions and post-formative evolution in setting present-day composition, yet secure measurements of CO and CH 4 in Jupiterfamily comets (JFCs) are especially sparse. The highly favorable 2018 apparition of JFC 21P/Giacobini-Zinner enabled a sensitive search for these "hypervolatiles" in a prototypical carbon-chain depleted comet. We observed 21P/Giacobini-Zinner with the iSHELL spectrograph at the NASA Infrared Telescope Facility on four preperihelion dates, two dates near-perihelion, and one post-perihelion date. We obtained detections of CO, CH 4 , and C 2 H 6 simultaneously with H 2 O on multiple dates. We present rotational temperatures, production rates, and mixing ratios. Combined with previous work, our results may indicate that the hypervolatile coma composition of 21P/ Giacobini-Zinner was variable across apparitions as well as within a particular perihelion passage, yet the spread in these measurements is a relatively small fraction of the variation in each molecule from comet to comet. We discuss the implications of our measured hypervolatile content of 21P/Giacobini-Zinner for the evolution of JFCs, and place our results in the context of findings from the Rosetta mission and ground-based studies of comets.

Published
2020

22. The surface distributions of the production of the major volatile species, H2O, CO2, CO and O2, from the nucleus of comet 67P/Churyumov-Gerasimenko throughout the Rosetta Mission as measured by the ROSINA double focusing mass spectrometer

Author

Kathrin Altwegg, Uwe Fink, Gabor Toth, Michael R. Combi, Yu-Chi Cheng, Kenneth C. Hansen, Nicolas Fougere, David Marshall, Tamas I. Gombosi, Martin Rubin, Fabrizio Capaccioni, Yinsi Shou, Dominique Bockelée-Morvan, Zhenguang Huang, Valeriy Tenishev, University of Michigan [Ann Arbor], University of Michigan System, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan System-University of Michigan System, Department of Climate and Space Sciences and Engineering (CLaSP), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], 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 e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, and Universiti Brunei Darussalam

Subjects
Atmospheres, 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, coma, Kinetic energy, Mass spectrometry, 01 natural sciences, 7. Clean energy, Article, law.invention, Atmosphere, Orbiter, law, 0103 physical sciences, Comets, structure, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Spectrometer, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], nucleus, Astronomy and Astrophysics, Atomic mass unit, Computational physics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) suite of instruments operated throughout the over two years of the Rosetta mission operations in the vicinity of comet 67P/Churyumov-Gerasimenko. It measured gas densities and composition throughout the comet's atmosphere, or coma. Here we present two-years' worth of measurements of the relative densities of the four major volatile species in the coma of the comet, H2O. CO2, CO and O2, by one of the ROSINA sub-systems called the Double Focusing Mass Spectrometer (DFMS). The absolute total gas densities were provided by the Comet Pressure Sensor (COPS), another ROSINA sub-system. DFMS is a very high mass resolution and high sensitivity mass spectrometer able to resolve at a tiny fraction of an atomic mass unit. We have analyzed the combined DFMS and COPS measurements using an inversion scheme based on spherical harmonics that solves for the distribution of potential surface activity of each species as the comet rotates, changing solar illumination, over short intervals and as the comet changes distance from the sun and orientation of its spin axis over long time intervals. We also use the surface boundary conditions derived from the inversion scheme to simulate the whole coma with our fully kinetic Direct Simulation Monte Carlo model and calculate the production rates of the four major species throughout the mission. We compare the derived production rates with revised remote sensing observations by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) as well as with published observations from the Microwave Instrument for the Rosetta Orbiter (MIRO). Finally we use the variation of the surface production of the major species to calculate the total mass loss over the mission and, for different estimates of the dust/gas ratio, calculate the variation of surface loss over the nucleus., 144 pages, 9 figures, 8 tables, 1 supplemental table

Published
2020

23. Spatial Distribution of Ultraviolet Emission from Cometary Activity at 67P/Churyumov-Gerasimenko

Author

Nicolas Biver, Joel Wm. Parker, Paul D. Feldman, Brian A. Keeney, Jean-Loup Bertaux, Ronald J. Vervack, Andrew J. Steffl, Seungwon Lee, John Noonan, Rebecca N. Schindhelm, Richard Medina, Harold A. Weaver, S. Alan Stern, Jon Pineau, Lori M. Feaga, Dominique Bockelée-Morvan, Mark Hofstadter, Michael F. A'Hearn, Matthew M. Knight, Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Physics [Annapolis], United States Naval Academy, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Ball Aerospace and Technologies Corp., Stellar Solutions, inc., SwRI Department of Space Operations [Boulder], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Comet volatiles, 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, Coma (optics), Context (language use), Astrophysics, medicine.disease_cause, 01 natural sciences, Spectral line, law.invention, Orbiter, law, 0103 physical sciences, Comets, Neutral coma gases, medicine, 010303 astronomy & astrophysics, Spectrograph, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Atomic emission spectroscopy, Small solar system bodies, Astronomy and Astrophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Ultraviolet, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Alice ultraviolet spectrograph on board the \textit{Rosetta} orbiter provided the first near-nucleus ultraviolet observations of a cometary coma from arrival at comet 67P/Churyumov-Gerasimenko in 2014 August through 2016 September. The characterization of atomic and molecular emissions in the coma revealed the unexpected contribution of dissociative electron impact emission at large heliocentric distances and during some outbursts. This mechanism also proved useful for compositional analysis, and Alice observed many cases that suggested elevated levels of the supervolatile \ce{O2}, identifiable in part to their emissions resulting from dissociative electron impact. In this paper we present the first two-dimensional UV maps constructed from Alice observations of atomic emission from 67P during an increase in cometary activity on 2015 November 7-8. Comparisons to observations of background coma and of an earlier collimated jet are used to describe possible changes to the near-nucleus coma and plasma. To verify the mapping method and place the Alice observations in context, comparisons to images derived from the MIRO and VIRTIS-H instruments are made. The spectra and maps we present show an increase in dissociative electron impact emission and an \ce{O2}/\ce{H2O} ratio of $\sim$0.3 for the activity; these characteristics have been previously identified with cometary outbursts seen in Alice data. Further, UV maps following the increases in activity show the spatial extent and emission variation experienced by the near-nucleus coma, informing future UV observations of comets that lack the same spatial resolution., Comment: 22 pages, 14 figures, 2 tables

Published
2021

24. How pristine is the interior of the comet 67P/Churyumov–Gerasimenko?

Author

Gianrico Filacchione, Ernesto Palomba, Mauro Ciarniello, Stefano Mottola, Alessandra Migliorini, Maria Teresa Capria, A. Zinzi, Dominique Bockelée-Morvan, C. Leyrat, Maria Cristina De Sanctis, Michelangelo Formisano, Andrea Raponi, Fabrizio Capaccioni, Andrea Longobardo, Ekkehard Kührt, Federico Tosi, Stéphane Erard, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Istituto de Astrofisica Spaziale et Fisica cosmica (IASF), 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), ITA, FRA, and DEU

Subjects
[PHYS]Physics [physics], Physics, 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Comet, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Astrobiology
Abstract

Comets are usually considered to be the most primitive bodies in the Solar System. The level of truth of this paradigm, however, is a matter of debate, especially if by primitive we mean that they represent a sample of intact, unprocessed material. We now have the possibility of analysing the comet 67P/Churyumov-Gerasimenko with an unprecedented level of detail, but its interior remains largely unprobed and unknown. The questions we address in this paper concern the depth of the processed layers, and whether the comet nucleus, under these processed layers, is really representative of the original material. We applied the Rome model for the thermal evolution and differentiation of nuclei to give an estimation of the evolution and depth of the active layers and of the interplay between the erosion process and the penetration of the heat wave. In order to characterize the illumination regime and the activity on the nucleus, two locations with very different illumination histories were chosen for the simulation. For both locations, the bulk of the activity tends to be concentrated around the perihelion time, giving rise to a high erosion rate. As a consequence, the active layers tend to remain close to the surface, and the interior of the comet, below a layer of few tens of centimetres, can be considered as pristine.

Published
2017

25. Long-term monitoring of the outgassing and composition of comet 67P/Churyumov-Gerasimenko with the Rosetta/MIRO instrument

Author

Mathieu Choukroun, W-H. Ip, N. Biver, Paul Hartogh, Jacques Crovisier, C. Leyrat, Dominique Bockelée-Morvan, F. P. Schloerb, M. Hofstadter, Emmanuel Lellouch, Samuel Gulkis, Pierre Encrenaz, Sukhan Lee, Ladislav Rezac, Gerard Beaudin, P. von Allmen, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, 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), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Max-Planck-Institut für Sonnensystemforschung (MPS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), 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), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
planetary systemssubmillimeter, 010504 meteorology & atmospheric sciences, Comet, Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, general -comets, Spectral line, Latitude, 0103 physical sciences, comets, individual, 67P/churyumov-Gerasimenko -radio lines, 010303 astronomy & astrophysics, planetary systems, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Jet (fluid), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Planetary system, Outgassing, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Nadir (topography)
Abstract

We present the analysis of ≈100 molecular maps of the coma of comet 67P/Churyumov-Gerasimenko that were obtained with the MIRO submillimeter radiotelescope on board the Rosetta spacecraft. From the spectral line mapping of H216O, H218O, H217O, CH3OH, NH3, and CO and some fixed nadir pointings, we retrieved the outgassing pattern and total production rates for these species. The analysis covers the period from July 2014, inbound to perihelion, to June 2016, outbound, and heliocentric distancesrh= 1.24–3.65 AU. A steep evolution of the outgassing rates with heliocentric distance is observed, typically inrh−16, with significant differences between molecules (e.g. steeper variation for H2O post-perihelion than for methanol). As a consequence, the abundances relative to water in the coma vary. The CH3OH and CO abundances increase after perihelion, while the NH3abundance peaks around perihelion and then decreases. Outgassing patterns have been modeled as 2D Gaussian jets. The width of these jets is maximum around the equinoxes when the bulk of the outgassing is located near the equator. From July 2014 to February 2015, the outgassing is mostly restricted to a narrower jet (full width at half-maximum ≈80°) originating from high northern latitudes, while around perihelion, most of the gaseous production comes from the southernmost regions ( − 80 ± 5° cometocentric latitude) and forms a 100°–130° (full width at half-maximum) wide fan. We find a peak production of water of 0.8 × 1028molec. s−1, 2.5 times lower than measured by the ROSINA experiment, and place an upper limit to a 50% additional production that could come from the sublimation of icy grains. We estimate the total loss of ices during this perihelion passage to be 4.18 ± 0.18 × 109kg. We derive a dust-to-gas ratio in the lost material of 0.7–2.3 (including all sources of errors) based on the nucleus mass loss of 10.5 ± 3.4 × 109kg estimated by the RSI experiment. We also obtain an estimate of the H218O/H217O ratio of 5.6 ± 0.8.

Published
2019

26. Terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets

Author

Dariusz C. Lis, C. Duran, Rolf Güsten, Helmut Wiesemeyer, Dominique Bockelée-Morvan, Jürgen Stutzki, Yoko Okada, Nicolas Biver, Yan Delorme, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), I. Physikalisches Institut [Köln], and Universität zu Köln

Subjects
Solar System, Planetesimal, Astrochemistry, 010504 meteorology & atmospheric sciences, Comet, Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, 0103 physical sciences, education, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, Astronomy and Astrophysics, Deuterium, 13. Climate action, Space and Planetary Science, Formation and evolution of the Solar System, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Water vapor, Astrophysics - Earth and Planetary Astrophysics
Abstract

The D/H ratio in cometary water has been shown to vary between 1 and 3 times the Earth's oceans value, in both Oort cloud comets and Jupiter-family comets originating from the Kuiper belt. We present new sensitive spectroscopic observations of water isotopologues in the Jupiter-family comet 46P/Wirtanen carried out using the GREAT spectrometer aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The derived D/H ratio of $(1.61 \pm 0.65) \times 10^{-4}$ is the same as in the Earth's oceans. Although the statistics are limited, we show that interesting trends are already becoming apparent in the existing data. A clear anti-correlation is seen between the D/H ratio and the active fraction, defined as the ratio of the active surface area to the total nucleus surface. Comets with an active fraction above 0.5 typically have D/H ratios in water consistent with the terrestrial value. These hyperactive comets, such as 46P/Wirtanen, require an additional source of water vapor in their coma, explained by the presence of subliming icy grains expelled from the nucleus. The observed correlation may suggest that hyperactive comets belong to a population of ice-rich objects that formed just outside the snow line, or in the outermost regions of the solar nebula, from water thermally reprocessed in the inner disk that was transported outward during the early disk evolution. The observed anti-correlation between the active fraction and the nucleus size seems to argue against the first interpretation, as planetesimals near the snow line are expected to undergo rapid growth. Alternatively, isotopic properties of water outgassed from the nucleus and icy grains may be different due to fractionation effects at sublimation. In this case, all comets may share the same Earth-like D/H ratio in water, with profound implications for the early solar system and the origin of Earth's oceans., Comment: 9 pages, 5 figures

Published
2019

27. The changing temperature of the nucleus of comet 67P induced by morphological and seasonal effects

Author

Ernesto Palomba, T. B. McCord, Batiste Rousseau, F. Mancarella, Sergio Fonti, Bernard Schmitt, Dominique Bockelée-Morvan, David Kappel, Mark Hofstadter, A. Zinzi, Gabriele Arnold, Mauro Ciarniello, J. Ph. Combe, Fabrizio Capaccioni, Giuseppe Piccioni, Alessandra Migliorini, Federico Tosi, J.-B. Vincent, Stéphane Erard, Giancarlo Bellucci, Priscilla Cerroni, Andrea Raponi, Johannes Benkhoff, D. Despan, Stefano Mottola, M. T. Capria, M. A. Barucci, Vincenzo Orofino, Gianrico Filacchione, Michelangelo Formisano, C. Leyrat, Andrea Longobardo, Ekkehard Kührt, M. C. De Sanctis, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), German Aerospace Center (DLR), Agenzia Spaziale Italiana (ASI), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Dipartimento di Fisica, Università degli studi di Lecce, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, 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]), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics [Lecce], Università del Salento [Lecce], Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], 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), Institut de recherches sur la catalyse (IRC), 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), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), 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), ITA, USA, FRA, DEU, Tosi, F., Capaccioni, F., Capria, M. T., Mottola, S., Zinzi, A., Ciarniello, M., Filacchione, G., Hofstadter, M., Fonti, S., Formisano, M., Kappel, D., Kührt, E., Leyrat, C., Vincent, J. -B., Arnold, G., De Sanctis, M. C., Longobardo, A., Palomba, E., Raponi, A., Rousseau, B., Schmitt, B., Barucci, M. A., Bellucci, G., Benkhoff, J., Bockelée-Morvan, D., Cerroni, P., Combe, J. -Ph., Despan, D., Erard, S., Mancarella, F., Mccord, T. B., Migliorini, A., Orofino, V., and Piccioni, G.

Subjects
Daytime, 010504 meteorology & atmospheric sciences, Infrared, Comet, Imaging spectrometer, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, law.invention, Orbiter, law, Phase (matter), 0103 physical sciences, medicine, Comets, Rosetta mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Diurnal temperature variation, Comet 67P/Churyumov-Gerasimenko thermal modeling temperature, Institut für Physik und Astronomie, Astronomy and Astrophysics, medicine.anatomical_structure, 13. Climate action, ddc:520, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus
Abstract

International audience; K nowledge of the surface temperature distribution of a comet's nucleus proves to be of fundamental importance for a number of reasons: the evaluation of the thermophysical properties (thermal inertia and roughness, at several spatial scales), the characterization of the thermal behaviour of peculiar surface units (for example, local ice exposures, or inherently cold material units not to be confused with shaded areas), and for the understanding of the physical processes affecting the surface and the shallow subsur-face layers (for example, sublimation of volatile compounds). The distribution of surface temperatures of a cometary nucleus, closely measured by a spacecraft, can be compared with theoretical models meant to predict the thermophysical properties of the nucleus at various depths and with previous thermal observations carried out by both Earth-based and space-based telescopes, with the goal of validating and/or improving those models 1. Furthermore, the temporal evolution of the surface temperatures, primarily driven by insolation, is critical in triggering the activity of a comet, allowing the migration of volatile compounds from the interior of the nucleus and the production of gas and dust observable with different techniques 2. In the past, thermal surveys of minor bodies were carried out using ground-based and space-based facilities. However, due to the limited spatial resolution of those observations, in most cases the derived thermal properties were only global averages, and the determined temperatures were highly model dependent. Before Rosetta, direct measurements of cometary nuclei surface temperatures were obtained during short periods for a handful of comets, namely 1P/ Halley 3 , 19P/Borrelly 4 , 9P/Tempel 1 1 and 103P/Hartley 2 5 , with a maximum spatial resolution of approximately 30 m per pixel. Here we study the surface temperature distribution of the nucleus of comet 67P/Churyumov-Gerasimenko as derived by the Visible InfraRed and Thermal Imaging Spectrometer, Mapping channel (VIRTIS-M, hereafter VIRTIS) 6 in Rosetta's early global mapping phase after comet encounter. These data cover the pre-perihelion period from 1 August to 23 September 2014, when the heliocentric distance decreased from 3.62 to 3.31 au and the spacecraft was in the altitude range 61-13 km above the surface, resulting in a spatial resolution from approximately 15 to 3 m per pixel (most data showing a resolution of 13 to 15 m per pixel). In this period, the solar phase angle ranged from 17° to 93°, which Knowledge of the surface temperature distribution on a comet's nucleus and its temporal evolution at different timescales is key to constraining its thermophysical properties and understanding the physical processes that take place at and below the surface. Here we report on time-resolved maps of comet 67P/Churyumov-Gerasimenko retrieved on the basis of infra-red data acquired by the Visible InfraRed and Thermal Imaging Spectrometer (VIRTIS) onboard the Rosetta orbiter in 2014, over a roughly two-month period in the pre-perihelion phase at heliocentric distances between 3.62 and 3.31 au from the Sun. We find that at a spatial resolution ≤15 m per pixel, the measured temperatures point out the major effect that self-heating, due to the complex shape of the nucleus, has on the diurnal temperature variation. The bilobate nucleus of comet 67P also induces daytime shadowing effects, which result in large thermal gradients. Over longer periods, VIRTIS-derived temperature values reveal seasonal changes driven by decreasing heliocentric distance combined with an increasing abundance of ice within the uppermost centimetre-thick layer, which implies the possibility of having a largely pristine nucleus interior already in the shallow subsurface.

Published
2019

28. ALMA Autocorrelation Spectroscopy of Comets: The HCN/H 13 CN Ratio in C/2012 S1 (ISON)

Author

M. Y. Palmer, Dariusz C. Lis, Steven B. Charnley, Stefanie N. Milam, Martin A. Cordiner, Geronimo Villanueva, N. Biver, J. Crovisier, Lucas Paganini, M. J. Mumma, Yi-Jehng Kuan, Dominique Bockelée-Morvan, Anthony J. Remijan, M. de Val-Borro, Departament d'Astronomia i Meteorologia [Barcelona] (DAM), Universitat de Barcelona (UB), NASA Goddard Space Flight Center (GSFC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), National Radio Astronomy Observatory (NRAO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, Astrochemistry, 010504 meteorology & atmospheric sciences, Autocorrelation, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful tool for high-resolution mapping of comets, but the main interferometer (comprised of 50x12-m antennas) is insensitive to the largest coma scales due to a lack of very short baselines. In this work, we present a new technique employing ALMA autocorrelation data (obtained simultaneously with the interferometric observations), effectively treating the entire 12-m array as a collection of single-dish telescopes. Using combined autocorrelation spectra from 28 active antennas, we recovered extended HCN coma emission from comet C/2012 S1 (ISON), resulting in a fourteen-fold increase in detected line brightness compared with the interferometer. This resulted in the first detection of rotational emission from H^13CN in this comet. Using a detailed coma radiative transfer model accounting for optical depth and non-LTE excitation effects, we obtained an H^12CN/H^13CN ratio of 88+-18, which matches the terrestrial value of 89, consistent with a lack of isotopic fractionation in HCN during comet formation in the protosolar accretion disk. The possibility of future discoveries in extended sources using autocorrelation spectroscopy from the main ALMA array is thus demonstrated.

Published
2019

29. Pronounced morphological changes in a southern active zone on comet 67P/Churyumov-Gerasimenko

Author

Pedro Hasselmann, Giampiero Naletto, Carsten Güttler, Horst Uwe Keller, Detlef Koschny, Philippe Lamy, J. M. Sunshine, J. D. P. Deshapriya, L. M. Lara, Francesco Marzari, M. De Cecco, S. Fornasier, R. Rodrigo, Holger Sierks, V. Da Deppo, Monica Lazzarin, G. Cremonese, Marco Fulle, Ivano Bertini, Björn Davidsson, Dennis Bodewits, P. J. Gutierrez, Cecilia Tubiana, Stefano Debei, Van H. Hoang, Xian Shi, M. A. Barucci, W-H. Ip, Clement Feller, J.-L. Bertaux, Dominique Bockelée-Morvan, J. J. Lopez-Moreno, Jakob Deller, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Physics [Hanoi], Vietnam Academy of Science and Technology (VAST), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Planetary Science Institute [Tucson] (PSI), University of Trento [Trento], ANR-17-CE31-0004,CLASSY,Composition des surfaces du Système Solaire de bas albédo(2017), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA)-European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and California Institute of Technology (CALTECH)-NASA

Subjects
67P/Churyumov-Gerasimenko - methods, 010504 meteorology & atmospheric sciences, Comet, Individual, Astrophysics, Fault scarp, 01 natural sciences, Indirect evidence, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, High spatial resolution, Comets, Active zone, miscellaneous [methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Miscellaneous, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Geodesy, 13. Climate action, Space and Planetary Science, methods: miscellaneous, Falling (sensation), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Production rate
Abstract

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., A smooth deposit in the southern Khonsu region has been seen in ESA/Rosetta observations as active during the second half of 2015, when the southern summer coincided with the perihelion passage of 67P/Churyumov-Gerasimenko (67P). Image color sequences acquired by the OSIRIS instrument in the period of January 2015 to July 2016, pre- and post-perihelion, show the occurrence of several small transient events as well as three massive outbursts (-10 to 1500 tons). High spatial resolution images taken one year and a half apart allowed us to track a variety of sources: the formation of cavities that are 1.3-14 m deep, ice-enriched patches, scarp retraction, and a second 50 m-wide boulder. We then estimated their masses and the dust mass of their corresponding plumes and outbursts. In particular, the deformation left by that boulder and its lack of talus may provide evidence for the lifting and subsequent falling back to the surface of large blocks. We calculate that a minimum vapor production rate of 1.4 x 10(24) m(-2) s(-1) is required to lift such an object. The comparison of the masses that are lost in the new cavities to the dust mass of outbursts gives indirect evidence of highly volatile ice pockets underneath. The spectrophotometric analysis and boulder counting also provides evidence for cavities that formed only 30 m apart with different spectral slopes, two long-standing ice patches, and local variations in the boulder-size frequency distribution. All this points to sub-surface ice pockets with different degrees of depth. Finally, the total mass of the morphological changes compared to most recent calculations of the total released mass by activity on 67P is estimated to be between 1.5 and 4.2%. This means that as many as about 25 similar active zones across the nucleus would be enough to sustain the entire cometary activity.© P. H. Hasselmann et al. 2019, P.H.H. would like to thank Alice Bernard for her support. This work was funded by the DIM-ACAV project (Ile-de-France). OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We acknowledge the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004).

Published
2019

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

Author

Stéphane Erard, Pierre Drossart, Mauro Ciarniello, Gabriele Arnold, M. T. Capria, David Kappel, Giovanna Rinaldi, Andrea Longobardo, F. Andrieu, Fabrizio Capaccioni, J. Crovisier, Fredric W. Taylor, Pedro Hasselmann, M. C. De Sanctis, Dominique Bockelée-Morvan, C. Leyrat, Gianrico Filacchione, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), DLR Institut für Planetenforschung, University of Oxford [Oxford], and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, Coma (optics), Astrophysics, Color temperature, 01 natural sciences, comets: individual: 67P, Phase (matter), 0103 physical sciences, infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Churyumov-Gerasimenko, Physics, [PHYS]Physics [physics], comets: general, Spectral properties, Leitungsbereich PF, Elevation, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We analyze 2–5μm spectroscopic observations of the dust coma of comet 67P/Churyumov-Gerasimenko obtained with the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-H) instrument on board Rosetta from 3 June to 29 October 2015 at heliocentric distancesrh= 1.24–1.55 AU. The 2–2.5μm color, bolometric albedo, and color temperature were measured using spectral fitting. Data obtained atα= 90° solar phase angle show an increase in bolometric albedo (0.05–0.14) with increasing altitude (0.5–8 km), accompanied by a possible marginal decrease in color and color temperature. Possible explanations include dark particles on ballistic trajectories in the inner coma and radial changes in particle composition. In the phase angle range 50°–120°, phase reddening is significant (0.031%/100 nm deg−1) for a mean color of 2%/100 nm atα= 90°, which might be related to the roughness of the dust particles. Moreover, a decrease in color temperature with decreasing phase angle is also observed at a rate of ~0.3 K deg−1, consistent with the presence of large porous particles, with low thermal inertia, and showing a significant day-to-night temperature contrast. Comparing data acquired at fixed phase angle (α= 90°), a 20% increase in bolometric albedo is observed near perihelion. Heliocentric variations in dust color are not significant in the time period we analyzed. The measured color temperatures vary from 260 to 320 K, and follow arh−0.6variation in therh= 1.24–1.5 AU range, which is close to the expectedrh−0.5value.

Published
2019

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

Author

Martin Hilchenbach, Klaus Hornung, Alberto Flandes, Jérémie Lasue, Anny Chantal Levasseur-Regourd, Giovanna Rinaldi, Stavro Ivanovski, Marco Fulle, Harald Krüger, Andrea Longobardo, Dominique Bockelée-Morvan, Dennis Bodewits, Stefano Mottola, Yves Langevin, C. Güttler, Gianrico Filacchione, Ivano Bertini, G. P. Tozzi, Holger Sierks, Jürgen Blum, J. Agarwal, Fabrizio Capaccioni, Giampiero Naletto, Thurid Mannel, F. Moreno, Alessandra Rotundi, Imre Tóth, Sihane Merouane, V. Della Corte, John Paquette, Cecilia Tubiana, Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Max-Planck-Institut für Sonnensystemforschung (MPS), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Institute of Physics [Graz], Karl-Franzens-Universität [Graz, Autriche], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astronomico di Trieste (OAT), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Milano] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astrofisico di Arcetri (OAA), Universität der Bundeswehr München [Neubiberg], Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Karl-Franzens-Universität Graz, Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), University of Graz, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Technische Universität Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ITA, FRA, DEU, and ESP

Subjects
Asteroiden und Kometen, instruments [space vehicles], 010504 meteorology & atmospheric sciences, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – space vehicles: instruments, Computer science, Comet, Individual, 01 natural sciences, Space exploration, Astrobiology, Interplanetary dust cloud, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, 67P/Churyumov-Gerasimenko - space vehicles, Comets, General - comets, Instruments, Instrumentation (computer programming), space vehicles: instruments, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Astronomy and Astrophysics, Common framework, Comets: general, [SDU]Sciences of the Universe [physics], Space and Planetary Science
Abstract

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., Before Rosetta, the space missions Giotto and Stardust shaped our view on cometary dust, supported by plentiful data from Earth based observations and interplanetary dust particles collected in the Earth's atmosphere. The Rosetta mission at comet 67P/Churyumov-Gerasimenko was equipped with a multitude of instruments designed to study cometary dust. While an abundant amount of data was presented in several individual papers, many focused on a dedicated measurement or topic. Different instruments, methods, and data sources provide different measurement parameters and potentially introduce different biases. This can be an advantage if the complementary aspect of such a complex data set can be exploited. However, it also poses a challenge in the comparison of results in the first place. The aim of this work therefore is to summarize dust results from Rosetta and before. We establish a simple classification as a common framework for intercomparison. This classification is based on the dust particle structure, porosity, and strength and also on its size. Depending on the instrumentation, these are not direct measurement parameters, but we chose them because they were the most reliable for deriving our model. The proposed classification has proved helpful in the Rosetta dust community, and we offer it here also for a broader context. In this manner, we hope to better identify synergies between different instruments and methods in the future.© C. Güttler et al. 2019

Published
2019

32. Molecular composition of comet 46P/Wirtanen from millimetre-wave spectroscopy

Author

N. Dello Russo, J. Crovisier, P. Colom, Dominique Bockelée-Morvan, Boncho P. Bonev, R. Moreno, Nathan Roth, Martin A. Cordiner, Nicolas Biver, Dariusz C. Lis, Jérémie Boissier, Stefanie N. Milam, Ronald J. Vervack, Michael A. DiSanti, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'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), Interactions Hôtes-Pathogènes-Environnements (IHPE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Perpignan Via Domitia (UPVD), Instituto Alexander Von Humboldt, Bogota, Colombia, NASA Goddard Space Flight Center (GSFC), Catholic University of America, Universities Space Research Association (USRA), American University Washington D.C. (AU), Johns Hopkins University (JHU), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), and GSFC Planetary Systems Laboratory

Subjects
Formamide, 010504 meteorology & atmospheric sciences, Mean kinetic temperature, radio lines: planetary systems, Comet, FOS: Physical sciences, Astrophysics, 01 natural sciences, Radio telescope, chemistry.chemical_compound, 0103 physical sciences, Molecule, Spectroscopy, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Millimetre wave, Earth and Planetary Astrophysics (astro-ph.EP), Physics, comets: general, submillimeter: planetary systems, Astronomy and Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, comets: individual: 46P/Wirtanen, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Ethylene glycol, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the results of a molecular survey of comet 46P/Wirtanen undertaken with the IRAM 30-m and NOEMA radio telescopes in December 2018. Observations at IRAM 30-m during the 12-18 Dec. period comprise a 2 mm spectral survey covering 25 GHz and a 1 mm survey covering 62 GHz. The gas outflow velocity and kinetic temperature have been accurately constrained by the observations. We derive abundances of 11 molecules, some being identified remotely for the first time in a Jupiter-family comet, including complex organic molecules such as formamide, ethylene glycol, acetaldehyde, or ethanol. Sensitive upper limits on the abundances of 24 other molecules are obtained. The comet is found to be relatively rich in methanol (3.4 percent relative to water), but relatively depleted in CO, CS, HNC, HNCO, and HCOOH., Comment: 35 pages, 16 figures, to be published in Astronomy & Astrophysics

Published
2021

33. L'étude des comètes en ondes radio

Author

P. Colom, Nicolas Biver, Dominique Bockelée-Morvan, Jacques Crovisier, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Solar System, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Chemical composition, Energy Engineering and Power Technology, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Physics and Astronomy(all), 01 natural sciences, Radio telescope, 0103 physical sciences, Comets, [CHIM]Chemical Sciences, Astrophysics::Solar and Stellar Astrophysics, Isotopologue, Comètes, Radio astronomy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Solar System formation, General Engineering, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Formation du système solaire, Composition chimique, Space observatory, Wavelength, 13. Climate action, Physics::Space Physics, Radioastronomie, Millimeter, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System, Astrophysics - Earth and Planetary Astrophysics
Abstract

Comets are considered as the most primitive objects in the Solar System. Their composition provides information on the composition of the primitive solar nebula, 4.6 Gyr ago. The radio domain is a privileged tool to study the composition of cometary ices. Observations of the OH radical at 18 cm wavelength allow us to measure the water production rate. A wealth of molecules (and some of their isotopologues) coming from the sublimation of ices in the nucleus have been identified by observations in the millimetre and submillimetre domains. We present an historical review on radio observations of comets, focusing on the results from our group, and including recent observations with the Nan\c{c}ay radio telescope, the IRAM antennas, the Odin satellite, the Herschel space observatory, ALMA, and the MIRO instrument aboard the Rosetta space probe., Comment: Proceedings of URSI France scientific days, "Probing Matter with Electromagnetic Waves", 24-25 March 2015, Paris. To be published in C. R. Physique

Published
2016
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34. A radiative transfer model to treat infrared molecular excitation in cometary atmospheres

Author

V. Debout, Dominique Bockelée-Morvan, Vladimir Zakharov, 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), Climate and Environmental Physics Laboratory [Russia], and Ural Federal University [Ekaterinburg] (UrFU)

Subjects
[PHYS]Physics [physics], Physics, 010504 meteorology & atmospheric sciences, Opacity, Infrared, Monte Carlo method, Flux, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Computational physics, Azimuth, Atmospheric radiative transfer codes, Space and Planetary Science, Excited state, 0103 physical sciences, Radiative transfer, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The exospheres of small Solar System bodies are now observed with high spatial resolution from space missions. Interpreting infrared spectra of cometary gases obtained with the VIRTIS experiment onboard the Rosetta cometary mission requires detailed modeling of infrared fluorescence emission in optically thick conditions. Efficient computing methods are required since numerous ro-vibrational lines excited by the Sun need to be considered. We propose a new model working in a 3-D environment to compute numerically the local incoming radiation. It uses a new algorithm using pre-defined directions of ray propagation and ray grids to reduce the CPU cost in time with respect to Monte Carlo methods and to treat correctly the sunlight direction. The model is applied to the ν 3 bands of CO 2 and H 2 O at 4.3 μ m and 2.7 μ m respectively, and to the CO ∨ ( 1 → 0 ) band at 4.7 μ m. The results are compared to the ones obtained by a 1-D algorithm which uses the Escape Probability (EP) method, and by a 3-D “Coupled Escape Probability” (CEP) model, for different levels of optical thickness. Our results suggest that the total band flux may vary strongly with azimuth for optically thick cases whereas the azimuth average total band flux computed is close to the one obtained with EP. Our model globally predicts less intensity reduction from opacity than the CEP model of Gersch and A’Hearn (Gersch, A.M., A’Hearn, M.F. [2014]. Astrophys. J. 787, 36–56). An application of the model to the observation of CO 2 , CO and H 2 O bands in 67/P atmosphere with VIRTIS is presented to predict the evolution of band optical thickness along the mission.

Published
2016

35. The extraordinary composition of the blue comet C/2016 R2 (PanSTARRS)

Author

Jacques Crovisier, Dominique Bockelée-Morvan, Gabriel Paubert, Raphael Moreno, E. Bertrand, Jérémie Boissier, Nicolas Biver, Michael A. DiSanti, H. Boussier, Adam J. McKay, N. Dello Russo, F. Kugel, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biologie et écologie tropicale et méditerranéenne [2007-2010] (BETM), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biologie et écologie tropicale et méditerranéenne (BETM), and Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, radio lines: planetary systems, Comet, FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, Radio telescope, Telescope, Abundance (ecology), law, 0103 physical sciences, Trans-Neptunian object, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Earth and Planetary Astrophysics (astro-ph.EP), comets: general, Astronomy and Astrophysics, submillimeter: planetary systems, 13. Climate action, Space and Planetary Science, comets: individual: C/2016 R2, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present a multi-wavelength study of comet C/2016 R2 (PanSTARRS). This comet was observed on 23-24 January 2018 with the IRAM 30m telescope, and in January to March 2018 with the Nan\c{c}ay radio telescope. Visible spectroscopy was performed in December 2017 and February 2018 with small amateur telescopes. We report on measurements of CO, CH3OH, H2CO and HCN production rates, and on the determination of the N2/CO abundance ratio. Several other species, especially OH, were searched for but not detected. The inferred relative abundances, including upper limits for sulfur species, are compared to those measured in other comets at about the same heliocentric distance of about 2.8 AU. The coma composition of comet C/2016 R2 is very different from all other comets observed so far, being rich in N2 and CO and dust poor. This suggests that this comet might belong to a very rare group of comets formed beyond the N2 ice line. Alternatively, comet C/2016 R2 (PanSTARRS) could be the fragment of a large and differentiated transneptunian object, with properties characteristic of volatile-enriched layers., Comment: 14 pages, 16 figures. Accepted for publication in Astronomy & Astrophysics

Published
2018

36. Summer outbursts in the coma of comet 67P/Churyumov-Gerasimenko as observed by Rosetta-VIRTIS

Author

David Kappel, Fabrizio Capaccioni, Dominique Bockelée-Morvan, Uwe Fink, Andrea Raponi, Stéphane Erard, V. Della Corte, Gianrico Filacchione, Andrea Longobardo, Alessandra Rotundi, M. T. Capria, Giovanna Rinaldi, M. Salatti, G. P. Tozzi, Alessandra Migliorini, Fredric W. Taylor, Federico Tosi, C. Leyrat, Ernesto Palomba, Mauro Ciarniello, Emiliano D'Aversa, S. Ivanovski, Lyn R. Doose, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Universita degli studi di Napoli 'Parthenope' [Napoli], and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis -methods:observational, Space vehicles: instruments, Techniques: imaging spectroscopy, Astronomy and Astrophysics, Space and Planetary Science, Comet, Imaging spectrometer, Coma (optics), Astrophysics, 01 natural sciences, 0103 physical sciences, Visible infrared, space vehicles: instruments, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Leitungsbereich PF, methods:observational, comets: individual: 67P/Churyumov-Gerasimenko, Methods observational, methods: data analysis, 13. Climate action, techniques: imaging spectroscopy, Rapid onset, Radiance, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present an analysis of transient events observed by the Visible InfraRed Thermal Imaging Spectrometer, instrument aboard Rosetta, for the dates of 2015 August 10, September 13 and 14, during the two months surrounding the comet perihelion passage of the Rosetta spacecraft. We detected and characterized events with life-times ranging from 26 min down to 6 min. The temporal evolution of the outburst shows a sudden increase of radiance from quiescent coma to the maximum in a few minutes. This rapid onset is correlated with a change of the visible dust colour from red, 15-18± 3 {{ per cent}}/100 nm, to bluer with values of 7-10± 0.3 {{ per cent}}/100 nm. The dust morphology of these outbursts can be classified into two main types: narrow and collimated plumes (August 10, September 13) and broad blobs (September 14). The observations suggest that there are localized regions on the surface that are more prone to outbursts than the rest of the nucleus. The projected dust velocity during the outburst events ranges between 22.2 ± 2.2 m s-1 and 64.9 ± 10.6 m s-1. The total ejected mass during an outburst event is estimated to be between 10 and 500 tons for a duration of 6-26 min assuming size distribution indices between -2.5 and -3.

Published
2018

37. 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

38. Models of Rosetta/OSIRIS 67P Dust Coma Phase Function

Author

Giovanna Rinaldi, Jean-Loup Bertaux, Carsten Güttler, Marco Fulle, Xian Shi, Giampiero Naletto, Jessica Agarwal, Stefano Mottola, Dominique Bockelée-Morvan, Olga Muñoz, Holger Sierks, F. Moreno, V. V. Zakharov, Francesco Marzari, M. De Cecco, V. Della Corte, Stavro Ivanovski, E. Frattin, Detlef Koschny, L. M. Lara, Björn Davidsson, Cecilia Tubiana, Wing-Huen Ip, Philippe Lamy, Ivano Bertini, S. Fornasier, H. U. Keller, Ludmilla Kolokolova, Monica Lazzarin, Gabriele Cremonese, J. J. López-Moreno, Alessandra Rotundi, Dennis Bodewits, Stefano Debei, Imre Tóth, D. Guirado, P. J. Gutierrez, Jakob Deller, Zhong-Yi Lin, M. A. Barucci, R. Rodrigo, V. Da Deppo, Polish Academy of Sciences, Ministerio de Economía y Competitividad (España), European Commission, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), National Central University [Taiwan] (NCU), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), and Technische Universität Braunschweig [Braunschweig]

Subjects
methods: numerical, minor planets, asteroids: individual (67P/Churyumov-Gerasimenko), Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Phase function, asteroids: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, asteroids: individual (67P), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Mission operations, numerical [Methods], biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], asteroids: individual (67P Churyumov–Gerasimenko), biology.organism_classification, individual (67P/Churyumov-Gerasimenko) [Minor planets,asteroids], minor planets, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Minor planets,asteroids: individual (67P/Churyumov-Gerasimenko), Astrophysics - Earth and Planetary Astrophysics
Abstract

The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images. This function shows a deep minimum at phase angles near 100°, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly oriented aggregate particles. We show, however, that an ensemble of oriented elongated particles of a wide variety of aspect ratios, with radii r 10 μm, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60%-70% range.© 2018. The American Astronomical Society. All rights reserved.., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire dAstrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politecnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB; grant No. 74/10: 2), and the ESA Technical Directorate is gratefully acknowledged. H.R. was also supported by grant No. 2011/01/B/ST9/05442 of the Polish National Science Center. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. This work was supported by contracts AYA2015-67152-R and AYA2015-71975-REDT from the Spanish Ministerio de Economia y Competitividad.

Published
2018

39. DIVISION F COMMISSION 15: PHYSICAL STUDY OF COMETS AND MINOR PLANETS

Author

Dominique Bockelée-Morvan, Ricardo Gil-Hutton, Daniel Hestroffer, Irina N. Belskaya, Björn J. R. Davidsson, Elisabetta Dotto, Alan Fitzsimmons, Hideyo Kawakita, Thais Mothe-Diniz, Javier Licandro, Diane H. Wooden, Hajime Yano, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Solar System, 010504 meteorology & atmospheric sciences, business.industry, Numerical modeling, Astronomy and Astrophysics, Commission, 01 natural sciences, Astrobiology, Geography, Space and Planetary Science, Asteroid, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Telecommunications, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Commission 15 of the International Astronomical Union (IAU), entitled Physical Study of Comets and Minor Planets, was founded in 1935 and dissolved in 2015, following the reorganization of IAU. In 80 years of Commission 15, tremendous progress has been made on the knowledge of these objets, thanks to the combined efforts of ground- and space-based observations, space mission rendezvous and flybys, laboratory simulation and analyses of returned samples, and theoretical and numerical modeling. Together with dynamical studies of the Solar System, this discipline has provided a much deeper understanding of how the Solar System formed and evolved. We present a legacy report of Commission 15, which highlights key milestones in the exploration and knowledge of the small bodies of the Solar System.

Published
2015

40. Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

Author

Anthony J. Remijan, Steven B. Charnley, Lucas Paganini, D. C. Lis, Geronimo L. Villanueva, Martin A. Cordiner, Nicolas Biver, Stefanie N. Milam, Dominique Bockelée-Morvan, Jérémie Boissier, M. J. Mumma, Iain Coulson, Jacques Crovisier, and Yi-Jehng Kuan

Subjects
Physics, Line-of-sight, 010504 meteorology & atmospheric sciences, Mean kinetic temperature, Comet, Astronomy and Astrophysics, Rotational temperature, Astrophysics, 01 natural sciences, Submillimeter Array, Space and Planetary Science, 0103 physical sciences, Radiative transfer, Millimeter, Emission spectrum, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (Trot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June,Trotfell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise inTrotat ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

Published
2015

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

Author

Gabriele Arnold, Eric Quirico, G. P. Tozzi, Fabrizio Capaccioni, Stefano Mottola, Alessandra Migliorini, M. I. Blecka, Pierre Drossart, M. Combes, Andrea Longobardo, N. Biver, Stéphane Erard, Dominique Bockelée-Morvan, C. Leyrat, Gianrico Filacchione, M. T. Capria, Giovanna Rinaldi, Jacques Crovisier, 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 Institute of Planetary Research, German Aerospace Center (DLR), INAF - Osservatorio Astrofisico di Arcetri (OAA), and Polska Akademia Nauk = Polish Academy of Sciences (PAN)

Subjects
Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Infrared, Comet dust, Comet, FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Comet nucleus, 0103 physical sciences, Ejecta, infrared: planetary systems, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Scattering, comets: general, Leitungsbereich PF, Astronomy, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, 13. Climate action, Space and Planetary Science, Absorption band, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present 2-5 $\mu$m spectroscopic observations of the dust coma of 67P/Churyumov-Gerasimenko obtained with the VIRTIS-H instrument onboard Rosetta during two outbursts that occurred on 2015, 13 September 13.6 h UT and 14 September 18.8 h UT at 1.3 AU from the Sun. Scattering and thermal properties measured before the outburst are in the mean of values measured for moderately active comets. The colour temperature excess (or superheat factor) can be attributed to submicrometre-sized particles composed of absorbing material or to porous fractal-like aggregates such as those collected by the Rosetta in situ dust instruments. The power law index of the dust size distribution is in the range 2-3. The sudden increase of infrared emission associated to the outbursts is correlated with a large increase of the colour temperature (from 300 K to up to 630 K) and a change of the dust colour at 2-2.5 $\mu$m from red to blue colours, revealing the presence of very small grains ($\leq$ 100 nm) in the outburst material. In addition, the measured large bolometric albedos ($\sim$ 0.7) indicate bright grains in the ejecta, which could either be silicatic grains, implying the thermal degradation of the carbonaceous material, or icy grains. The 3-$\mu$m absorption band from water ice is not detected in the spectra acquired during the outbursts, whereas signatures of organic compounds near 3.4 $\mu$m are observed in emission. The H$_2$O 2.7-$\mu$m and CO$_2$ 4.3-$\mu$m vibrational bands do not show any enhancement during the outbursts., Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2017

42. Rosetta Alice/VIRTIS observations of the water vapour UV electroglow emissions around comet 67P/Churyumov-Gerasimenko

Author

George Clark, Harold A. Weaver, John Noonan, Gianrico Filacchione, Stéphane Erard, Lori M. Feaga, James L. Burch, Paul D. Feldman, T. W. Broiles, Jean-Loup Bertaux, Fabrizio Capaccioni, Andrew J. Steffl, S. Alan Stern, Eric Schindhelm, Joel Wm. Parker, Dominique Bockelée-Morvan, C. Leyrat, Michael F. A'Hearn, Marilia Samara, Jean-Yves Chaufray, Brian A. Keeney, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), NASA Goddard Space Flight Center (GSFC), IMPEC - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, and 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)

Subjects
Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], education.field_of_study, Electron density, Brightness, 010504 meteorology & atmospheric sciences, 67P/CG, Comet, Population, Astronomy and Astrophysics, Electron, 7. Clean energy, 01 natural sciences, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Radiation mechanism, Emission spectrum, Atomic physics, education, 010303 astronomy & astrophysics, Water vapor, Excitation, 0105 earth and related environmental sciences
Abstract

International audience; Several UV emission lines of the coma of 67P/Churyumov-Gerasimenko have been observed by Alice/Rosetta before the 67P/CG perihelion. The H and O emissions are mainly produced by impact dissociation of water molecules by suprathermal electrons. In this paper we explore further the electron dissociative excitation of H2O to produce the UV emissions by using simultaneous observations of water and H Lyman-β done by the VIRTIS-H and Alice instruments during four periods of time in 2014 December, 2015 March and 2015 May. We used simple theoretical considerations to link the UV brightness to the water vapour column density.Two cases are studied. In the first case, we assume the suprathermal electron density is decreasing radially as the thermal electron population, in the second case we assume the suprathermal electron density does not vary radially. The second case seems more consistent with the RPC-IES measurements during 2015 March and May. The efficiency of the electron dissociative excitation of H2O is lower during the three last periods of time studied compared to the first period in 2014 December. The variability of the efficiency of the electron dissociative excitation between the four studied periods is not simply inversely proportional to the square of the comet sun distance but is most likely associated with the variability of the suprathermal electron distribution.

Published
2017

43. Spatially resolved evolution of the local H 2 O production rates of comet 67P/Churyumov-Gerasimenko from the MIRO instrument on Rosetta

Author

Wing-Huen Ip, N. Biver, Ladislav Rezac, P. von Allmen, David Marshall, Paul Hartogh, Dominique Bockelée-Morvan, Mark Hofstadter, Christopher Jarchow, Pierre Encrenaz, Jacques Crovisier, Samuel Gulkis, Seungwon Lee, Emmanuel Lellouch, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, 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 d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Electrical Engineering (DEE-POSTECH), Pohang University of Science and Technology (POSTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Jet Propulsion Laboratory, California Institute of Technology (JPL), 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 École normale supérieure - Paris (ENS-PSL)

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Continuum (design consultancy), Comet, Astronomy and Astrophysics, Astrophysics, Spatial distribution, 01 natural sciences, Outgassing, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Nadir, Sublimation (phase transition), Variation (astronomy), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation)
Abstract

International audience; Aims: Using spectroscopic and continuum data measured by the MIRO instrument on board Rosetta of comet 67P/Churyumov-Gerasimenko, it is possible to derive and track the change in the water production rate, to learn how the outgassing evolves with heliocentric distance. The MIRO data are well suited to investigate the evolution of 67P, in unprecedented spatial and temporal detail. Methods: To obtain estimates of the local effective Haser production rates we developed an efficient and reliable retrieval approach with precalculated lookup tables. We employed line area ratios (H216O/H218O) from pure nadir observations as the key variable, along with the Doppler shift velocity, and continuum temperature. This method was applied to the MIRO data from August 2014 until April 2016. Perihelion occurred on August 13, 2015 when the comet was 1.24 AU from the Sun. Results: During the perihelion approach, the water production rates increased by an order of magnitude, and from the observations, the derived maximum for a single observation on August 29, 2015 is (1.42 ± 0.51) ×1028. Modeling the data indicates that there is an offset in the peak outgassing, occurring 34 ± 10 days after perihelion. During the pre-perihelion phase, the production rate changes with heliocentric distance as rh-3.8±0.2; during post-perihelion, the dependence is rh-4.3±0.2. The comet is calculated to have lost 0.12 ± 0.06 % of its mass during the perihelion passage, considering only water ice sublimation. Additionally, this method provides well sampled data to determine the spatial distribution of outgassing versus heliocentric distance. The time evolution is definitely not uniform across the surface. Pre- and post-perihelion, the surface temperature on the southern hemisphere changes rapidly, as does the sublimation rate with an exponent of -6. There is a strong latitudinal dependence on the rh exponent with significant variation between northern and southern hemispheres, and so the average over the comet surface may only be of limited importance. We present more detailed regional variation in the outgassing, demonstrating that the highest derived production rates originate from the Wosret, Neith and Bes regions during perihelion.

Published
2017

44. The composition of cometary ices

Author

Nicolas Biver, Dominique Bockelée-Morvan, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS]Physics [physics], Solar System, 010504 meteorology & atmospheric sciences, General Mathematics, Comet, General Engineering, General Physics and Astronomy, Astronomy, 01 natural sciences, Organic molecules, Astrobiology, 13. Climate action, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Chemical composition, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The chemical composition of cometary ices provides clues for the conditions of formation and evolution of the early Solar System. A large number of molecules have been identified in cometary atmospheres, from both ground-based observations and space, includingin situinvestigations. This includes large organic molecules, which are also observed in star-forming regions. This paper presents a review of molecular abundances measured in cometary atmospheres from remote sensing observations with ground-based and space-based telescopes. The diversity of composition observed in comet populations is presented and discussed.This article is part of the themed issue ‘Cometary science after Rosetta’.

Published
2017

45. Detection of CO and HCN in Pluto’s atmosphere with ALMA

Author

Xun Zhu, Panayotis Lavvas, Bruno Sicardy, Emmanuel Lellouch, R. Moreno, Alan Stern, Eliot F. Young, Bryan J. Butler, Thierry Fouchet, Harold A. Weaver, Leslie A. Young, Mark Gurwell, Dominique Bockelée-Morvan, John Stansberry, Darrell F. Strobel, Jérémie Boissier, N. Biver, Arielle Moullet, Dariusz C. Lis, 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), Centre for Astronomy, Harvard University, Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Harvard University [Cambridge], École normale supérieure - Paris (ENS Paris), Biologie et écologie tropicale et méditerranéenne [2007-2010] (BETM), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Materials science, 010504 meteorology & atmospheric sciences, Condensation, Analytical chemistry, FOS: Physical sciences, Astronomy and Astrophysics, Atmospheric sciences, Mole fraction, 01 natural sciences, Mesosphere, Pluto, Atmosphere, 13. Climate action, Space and Planetary Science, Stratopause, 0103 physical sciences, Cloud condensation nuclei, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract

Observations of the Pluto-Charon system, acquired with the ALMA interferometer on June 12-13, 2015, have yielded a detection of the CO(3-2) and HCN(4-3) rotational transitions from Pluto, providing a strong confirmation of the presence of CO, and the first observation of HCN, in Pluto's atmosphere. The CO and HCN lines probe Pluto's atmosphere up to ~450 km and ~900 km altitude, respectively. The CO detection yields (i) a much improved determination of the CO mole fraction, as 515+/-40 ppm for a 12 ubar surface pressure (ii) clear evidence for a well-marked temperature decrease (i.e., mesosphere) above the 30-50 km stratopause and a best-determined temperature of 70+/-2 K at 300 km, in agreement with recent inferences from New Horizons / Alice solar occultation data. The HCN line shape implies a high abundance of this species in the upper atmosphere, with a mole fraction >1.5x10-5 above 450 km and a value of 4x10-5 near 800 km. The large HCN abundance and the cold upper atmosphere imply supersaturation of HCN to a degree (7-8 orders of magnitude) hitherto unseen in planetary atmospheres, probably due to the slow kinetics of condensation at the low pressure and temperature conditions of Pluto's upper atmosphere. HCN is also present in the bottom ~100 km of the atmosphere, with a 10-8 - 10-7 mole fraction; this implies either HCN saturation or undersaturation there, depending on the precise stratopause temperature. The HCN column is (1.6+/-0.4)x10^14 cm-2, suggesting a surface-referred net production rate of ~2x10^7 cm-2s-1. Although HCN rotational line cooling affects Pluto's atmosphere heat budget, the amounts determined in this study are insufficient to explain the well-marked mesosphere and upper atmosphere's ~70 K temperature. We finally report an upper limit on the HC3N column density (< 2x10^13 cm-2) and on the HC15N / HC14N ratio (< 1/125)., Revised version. Icarus, in press, Oct. 11, 2016. 57 pages, including 13 figures and 4 tables

Published
2017

46. Thermal Physics of the Inner Coma: ALMA Studies of the Methanol Distribution and Excitation in Comet C/2012 K1 (PanSTARRS)

Author

Nicolas Biver, Yi-Jehng Kuan, Anthony J. Remijan, Geronimo L. Villanueva, Martin A. Cordiner, Jérémie Boissier, J. Crovisier, Dariusz C. Lis, Dominique Bockelée-Morvan, Steven B. Charnley, Lucas Paganini, Iain Coulson, M. J. Mumma, Stefanie N. Milam, 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), NASA Goddard Space Flight Center (GSFC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Biologie et écologie tropicale et méditerranéenne [2007-2010] (BETM), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Mean kinetic temperature, Radiative cooling, Comet, FOS: Physical sciences, Astronomy and Astrophysics, Rotational temperature, Coma (optics), Astrophysics, 01 natural sciences, Submillimeter Array, Space and Planetary Science, 0103 physical sciences, Millimeter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Excitation, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

We present spatially and spectrally-resolved observations of CH$_3$OH emission from comet C/2012 K1 (PanSTARRS) using The Atacama Large Millimeter/submillimeter Array (ALMA) on 2014 June 28-29. Two-dimensional maps of the line-of-sight average rotational temperature ($T_{rot}$) were derived, covering spatial scales $0.3''-1.8''$ (corresponding to sky-projected distances $\rho\sim500$-2500 km). The CH$_3$OH column density distributions are consistent with isotropic, uniform outflow from the nucleus, with no evidence for extended sources of CH$_3$OH in the coma. The $T_{rot}(\rho)$ radial profiles show a significant drop within a few thousand kilometers of the nucleus, falling from about 60 K to 20 K between $\rho=0$ and 2500 km on June 28, whereas on June 29, $T_{rot}$ fell from about 120 K to 40 K between $\rho=$ 0 km and 1000 km. The observed $T_{rot}$ behavior is interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling of the outflowing gas, as well as radiative cooling of the CH$_3$OH rotational levels. Our excitation model shows that radiative cooling is more important for the $J=7-6$ transitions (at 338 GHz) than for the $K=3-2$ transitions (at 252 GHz), resulting in a strongly sub-thermal distribution of levels in the $J=7-6$ band at $\rho\gtrsim1000$ km. For both bands, the observed temperature drop with distance is less steep than predicted by standard coma theoretical models, which suggests the presence of a significant source of heating in addition to the photolytic heat sources usually considered., Comment: Accepted for publication in ApJ, January 2017

Published
2017

48. The Composition of Comets

Author

Anita L. Cochran, Anny-Chantal Levasseur-Regourd, Martin Cordiner, Edith Hadamcik, Jérémie Lasue, Adeline Gicquel, David G. Schleicher, Steven B. Charnley, Michael J. Mumma, Lucas Paganini, Dominique Bockelée-Morvan, Nicolas Biver, and Yi-Jehng Kuan

Subjects
010504 meteorology & atmospheric sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2017

49. Cometary Isotopic Measurements

Author

Dominique Bockelée-Morvan, Ursina Calmonte, Steven Charnley, Jean Duprat, Cécile Engrand, Adeline Gicquel, Myrtha Hässig, Emmanuël Jehin, Hideyo Kawakita, Bernard Marty, Stefanie Milam, Andrew Morse, Philippe Rousselot, Simon Sheridan, and Eva Wirström

Subjects
010504 meteorology & atmospheric sciences, 13. Climate action, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2017

50. Production of O2 through dismutation of H2O2 during water ice desorption: a key to understanding comet O2 abundances

Author

Marco Minissale, Dominique Bockelée-Morvan, François Dulieu, LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and École normale supérieure - Paris (ENS Paris)

Subjects
Astrochemistry, Abundance (chemistry), Comet, Evaporation, methods: laboratory: molecular, Context (language use), Astrophysics, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Astrobiology, chemistry.chemical_compound, Desorption, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, astrochemistry, comets: general, Astronomy and Astrophysics, Silicate, 0104 chemical sciences, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. Detection of molecular oxygen and prediction of its abundance have long been a challenge for astronomers. The low abundances observed in few interstellar sources are well above the predictions of current astrochemical models. During the Rosetta mission, an unexpectedly high abundance of O2 was discovered in the comet 67P/Churyumov-Gerasimenko’s coma. A strong correlation between O2 and H2O productions is observed, whereas no such correlation is observed between O2 and either of CO or N2. Aims. We suggest that the O2 molecule may be formed during the evaporation of water ice. We propose a possible reaction: the dismutation of H2O2 (2 H2O2−→ 2 H2O + O2), a molecule which should be co-produced during the water ice mantle growth on dust grains. We aim to test this hypothesis under realistic experimental conditions. Methods. We performed two sets of experiments. They consist of producing a mixture of D2O and D2O2 via the reaction of O2 and D on a surface held at 10 K. The first set is made on a silicate substrate, and explores the limit of thin films, in order to prevent any complication due to trapping during the desorption. The second set is performed on a pre-deposited H2O ice substrate and mimics the desorption of mixed ice. Results. In thin films, O2 is produced by the dismutation of H2O2, even at temperatures as low as 155 K. Mixed with water, H2O2 desorbs after the water ice sublimation and even more desorption of O2 is observed. Conclusions. H2O2, synthesised during the growth of interstellar ices (or by later processing), desorbs at the latest stage of the water sublimation and undergoes the dismutation reaction. Therefore an O2 release in the gas phase should occur at the end of the evaporation of ice mantles. Temperature gradients along the geometry of clouds, or interior of comets, should blend the different stages of the sublimation. Averaged along the whole process, a mean value of the O2/H2O ratio of a few percent in the gas phase seems plausible.

Published
2017

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