VIRTIS-H observations of the dust coma of comet 67P/Churyumov-Gerasimenko: spectral properties and color temperature variability with phase and elevation
| Autor: | 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 |
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| Přispěvatelé: | 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], PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
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 |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 630, pp.A22. ⟨10.1051/0004-6361/201834764⟩ |
| ISSN: | 0004-6361 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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