Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations

A.-T. Auger (1, 2) , Olivier Groussin (1) , Laurent Jorda (1) , S. Bouley (3, 2) , R. Gaskell (4) , Philippe L. Lamy (1) , C. Capanna (1) , Nicholas Thomas (5) , A. Pommerol (5) , Holger Sierks (6) , C. Barbieri (7) , R. Rodrigo (8, 9) , Detlef Koschny (10) , Hans Rickman (11, 12) , Horst U. Keller (13) , Jessica Agarwal (6) , Michael F. A'Hearn (14) , M. A. Barucci (15) , Jean-Loup Bertaux (16) , Ivano Bertini (17) , Gabriele Cremonese (18) , Vania Da Deppo (19) , Björn Davidsson (12) , Stefano Debei (18) , Mariolino De Cecco (20) , M. R. El-Maarry (5) , Sonia Fornasier (21, 15) , Marco Fulle (22) , Pedro J. Gutiérrez (23) , Carsten Güttler (6) , Stubbe Hviid (24) , W.-H Ip (25) , Jörg Knollenberg (24) , J.-R. Kramm (6) , Ekkehard Kührt (24) , Michael Küppers (26) , Florangela La Forgia (7) , Luisa M. Lara (23) , M. Lazzarin (7) , Jose J. Lopez Moreno (23) , S. Marchi (27) , Francesco Marzari (7) , Matteo Massironi (28, 17) , Harald Michalik (29) , Giampiero Naletto (30, 17, 19) , Nilda Oklay (6) , Maurizio Pajola (17) , L. Sabau (31) , Cécilia Tubiana (6) , Jean-Baptiste Vincent (6) , K.-P. Wenzel (10)

1 LAM - Laboratoire d'Astrophysique de Marseille
2 GEOPS - Géosciences Paris Sud
3 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides
4 PSI - Planetary Science Institute [Tucson]
5 Physikalisches Institut [Bern]
6 MPS - Max-Planck-Institut für Sonnensystemforschung
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 ISSI - International Space Science Institute [Bern]
9 CAB - Centro de Astrobiologia [Madrid]
10 RSSD - Research and Scientific Support Department, ESTEC
11 CBK - Space Research Centre of Polish Academy of Sciences
12 Department of Physics and Astronomy [Uppsala]
13 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
14 Department of Astronomy [College Park]
15 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
16 PLANETO - LATMOS
17 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
18 Department of Industrial Engineering [Padova]
19 IFN - CNR Institute for Photonics and Nanotechnologies
20 University of Trento [Trento]
21 UPD7 - Université Paris Diderot - Paris 7
22 OAT - INAF - Osservatorio Astronomico di Trieste
23 IAA - Instituto de Astrofísica de Andalucía
24 DLR Institute of Planetary Research
25 Institute of Space Science [Taiwan]
26 Operations Department (ESAC)
27 SSERVI - Solar System Exploration Research Virtual Institute
28 OAPD - INAF - Osservatorio Astronomico di Padova
29 Institut für Datentechnik und Kommunikationsnetze
30 DEI - Department of Information Engineering [Padova]
31 INTA - Instituto Nacional de Técnica Aeroespacial

Since August 2014, the OSIRIS Narrow Angle Camera (NAC) onboard the Rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko, down to the decimeter scale. This paper focuses on the Imhotep region, located on the largest lobe of the nucleus, near the equator. Aims. We map, inventory, and describe the geomorphology of the Imhotep region. We propose and discuss some processes to explain the formation and ongoing evolution of this region. Methods. We used OSIRIS NAC images, gravitational heights and slopes, and digital terrain models to map and measure the mor- phologies of Imhotep. Results. The Imhotep region presents a wide variety of terrains and morphologies: smooth and rocky terrains, bright areas, linear features, roundish features, and boulders. Gravity processes such as mass wasting and collapse play a significant role in the geomor- phological evolution of this region. Cometary processes initiate erosion and are responsible for the formation of degassing conduits that are revealed by elevated roundish features on the surface. We also propose a scenario for the formation and evolution of the Imhotep region; this implies the presence of large primordial voids inside the nucleus, resulting from its formation process.

Keywords: Data analysis; Comets; 67P/Churyumov-Gerasimenko

Domains: Earth and Planetary Astrophysics [astro-ph.EP]

A.-T. Auger, Olivier Groussin, Laurent Jorda, S. Bouley, R. Gaskell, et al.. Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations. Astronomy and Astrophysics - A&A, 2015, 583, A35 (13 p.). ⟨10.1051/0004-6361/201525947⟩. ⟨insu-01205392⟩