Constraints on cometary surface evolution derived from a statistical analysis of 67P’s topography

Jean-Baptiste Vincent (1) , Stubbe F. Hviid (1) , Stefano Mottola (1) , Ekkehard Kührt (1) , Frank Preusker (1) , Frank Scholten (1) , Horst Uwe Keller (2) , Nilda Oklay (1) , Detlef de Niem (1) , Björn Davidsson (3) , Marco Fulle (4) , Maurizio Pajola (5, 6) , Marc Hofmann (7) , Xuanyu Hu (7) , Hans Rickman (8, 9) , Zhong-Yi Lin (10) , Clément Feller (11) , Adeline Gicquel (3) , Steve Boudreault (3) , Holger Sierks (7) , Cesare Barbieri (12) , Philippe L. Lamy (13) , Rafael Rodrigo (14, 15) , Detlef Koschny (16) , Michael F. A'Hearn (2) , Maria Antonella Barucci (11) , Jean-Loup Bertaux (17) , Ivano Bertini (6) , Gabriele Cremonese (18) , Vania da Deppo (19) , Stefano Debei (20) , Mariolino de Cecco (21) , Jakob Deller (7) , Sonia Fornasier (11) , Olivier Groussin (13) , Pedro J. Gutiérrez (22) , Pablo Gutiérrez-Marquez (7) , Carsten Güttler (7) , Wing-Huen Ip (23, 10) , Laurent Jorda (13) , Jörg Knollenberg (1) , Gabor Kovacs (7, 24) , Jörg-Rainer Kramm (7) , Michael Küppers (25) , Luisa Lara (22) , Monica Lazzarin (12) , José J. Lopez Moreno (22) , Francesco Marzari (12) , Giampiero Naletto (24, 6, 19) , Luca Penasa (26) , Xian Shi (7) , Nicolas Thomas (27, 28) , Imre Toth (13, 29) , Cécilia Tubiana (7)

1 DLR Institut für Planetenforschung
2 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
3 JPL - Jet Propulsion Laboratory
4 OAT - INAF - Osservatorio Astronomico di Trieste
5 ARC - NASA Ames Research Center
6 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
7 MPS - Max-Planck-Institut für Sonnensystemforschung
8 Department of Physics and Astronomy [Uppsala]
9 CBK - Space Research Centre of Polish Academy of Sciences
10 Department of Astronomy [College Park]
11 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
12 Dipartimento di Fisica e Astronomia "Galileo Galilei"
13 LAM - Laboratoire d'Astrophysique de Marseille
14 CAB - Centro de Astrobiologia [Madrid]
15 ISSI - International Space Science Institute [Bern]
16 ESTEC - European Space Research and Technology Centre
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 IAA - Instituto de Astrofísica de Andalucía
23 SSI - Space Science Institute [Macau]
24 DEI - Department of Information Engineering [Padova]
25 Operations Department (ESAC)
26 Dipartimento di Geoscienze [Padova]
27 CSH - Center for Space and Habitability
28 Physikalisches Institut [Bern]
29 Konkoly Observatory

We present a statistical analysis of the distribution of large scale topographic features on comet 67P/Churyumov-Gerasimenko. We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to −1.69 ± 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the northern hemisphere topography is dominated by structures on the 100 m scale while the southern hemisphere topography, illuminated at perihelion, is dominated by 10 m scale terrain features. Our study suggest that the current size of a cliff is controlled not only by material cohesion but by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet’s erosional history, i.e. its evolutionary age.

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]; Earth and Planetary Astrophysics [astro-ph.EP]; Sciences of the Universe [physics]; Astrophysics [astro-ph]; Solar and Stellar Astrophysics [astro-ph.SR]; Physics [physics]; Physics [physics]; Astrophysics [astro-ph]

Jean-Baptiste Vincent, Stubbe F. Hviid, Stefano Mottola, Ekkehard Kührt, Frank Preusker, et al.. Constraints on cometary surface evolution derived from a statistical analysis of 67P’s topography. Monthly Notices of the Royal Astronomical Society, 2017, 469 (Suppl_2), pp.S329-S338. ⟨10.1093/mnras/stx1691⟩. ⟨insu-01574951⟩