Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past

Mohamed Ramy El-Maarry (1, 2) , Olivier Groussin (3) , Nicholas Thomas (2) , Maurizio Pajola (4) , Anne-Thérèse Auger (3) , Björn Davidsson (5) , X. Hu (6) , Stubbe F. Hviid (7) , Jörg Knollenberg (7) , Carsten Güttler (6) , Cécilia Tubiana (6) , Sonia Fornasier (8) , Clément Feller (8) , Pedro H. Hasselmann (8) , Jean-Baptiste Vincent (7) , Holger Sierks (6) , Cesare Barbieri (9) , Philippe Lamy (3) , Rafael Rodrigo (10, 11) , Detlef Koschny (12) , Horst U. Keller (13, 7) , Hans Rickman (14, 15) , Michael F. A'Hearn (16) , Maria Antonella Barucci (8) , Jean-Loup Bertaux (17) , Ivano Bertini (9) , Sébastien Besse (12) , Dennis Bodewits (16) , Gabriele Cremonese (18) , Vania da Deppo (19) , Stefano Debei (20) , Mariolino de Cecco (21) , Jakob Deller (6) , J. D. P. Deshapriya (8) , Marco Fulle (22) , Pedro J. Gutiérrez (23) , Marc Hofmann (6) , Wing-Huen Ip (24) , Laurent Jorda (3) , Gabor Kovacs (6) , J.-Rainer Kramm (6) , Ekkehard Kührt (7) , Michael Küppers (25) , Luisa M. Lara (23) , Monica Lazzarin (9) , Zhong-Yi Lin (24) , José J. Lopez Moreno (23) , Simone Marchi (26) , Francesco Marzari (9) , Stefano Mottola (7) , Giampiero Naletto (27, 19, 28) , Nilda Oklay (6) , Antoine Pommerol (2) , Frank Preusker (7) , Frank Scholten (7) , Xian Shi (6)

1 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
2 Physikalisches Institut [Bern]
3 LAM - Laboratoire d'Astrophysique de Marseille
4 ARC - NASA Ames Research Center
5 JPL - Jet Propulsion Laboratory
6 MPS - Max-Planck-Institut für Sonnensystemforschung
7 DLR Institut für Planetenforschung
8 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
9 Dipartimento di Fisica e Astronomia "Galileo Galilei"
10 ISSI - International Space Science Institute [Bern]
11 CAB - Centro de Astrobiologia [Madrid]
12 Operations Department (ESAC)
13 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
14 CBK - Space Research Centre of Polish Academy of Sciences
15 Department of Physics and Astronomy [Uppsala]
16 Department of Astronomy [College Park]
17 PLANETO - LATMOS
18 OAPD - INAF - Osservatorio Astronomico di Padova
19 IFN - CNR Institute for Photonics and Nanotechnologies
20 Department of Industrial Engineering [Padova]
21 University of Trento [Trento]
22 OAT - INAF - Osservatorio Astronomico di Trieste
23 IAA - Instituto de Astrofísica de Andalucía
24 IANCU - Institute of Astronomy [Taiwan]
25 ESAC - European Space Astronomy Centre
26 SSERVI - Solar System Exploration Research Virtual Institute
27 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
28 DEI - Department of Information Engineering [Padova]

The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet’s landscape. This suggests that most of the major landforms were created early in the comet’s current orbital configuration. They may even date from earlier if the comet had a larger volatile inventory, particularly of CO or CO2 ices, or contained amorphous ice, which could have triggered activity at greater distances from the Sun.

Domains: Earth and Planetary Astrophysics [astro-ph.EP]; Solar and Stellar Astrophysics [astro-ph.SR]

Mohamed Ramy El-Maarry, Olivier Groussin, Nicholas Thomas, Maurizio Pajola, Anne-Thérèse Auger, et al.. Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past. Science, 2017, 355 (6332), pp.1392 - 1395. ⟨10.1126/science.aak9384⟩. ⟨insu-01511121⟩