Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images

M.R. El-Maarry 1 Nicholas Thomas 1 L. Giacomini 2 M. Massironi 2 M. Pajola 3 R. Marschall 1 A. Gracia-Berná 1 H. Sierks 4 C. Barbieri 5 Philippe L. Lamy 6 R. Rodrigo 7, 8 H. Rickman 9, 10 Detlef Koschny 11 H. U. Keller 12 J. Agarwal 4 M. F. A’hearn 13 A-T. Auger 6 Maria A. Barucci 14 Jean-Loup Bertaux 15 I. Bertini 3 S. Besse 11 D. Bodewits 13 Gabriele Cremonese 16 V. Da Deppo 17 B. Davidsson 9 M. De Cecco 18 S. Debei 19 Carsten Güttler 4 Sonia Fornasier 14, 20 M. Fulle 21 Olivier Groussin 6 Pedro J. Gutierrez 22 S. F. Hviid 23 W-H. Ip 24 Laurent Jorda 6 Jörg Knollenberg 23 G. Kovacs 4 J.-R. Kramm 4 E. Kührt 23 M. Küppers 25 Florangela La Forgia 16 Luisa M. Lara 22 M. Lazzarin 5 José J. Lopez Moreno 22 S. Marchi 26 F. Marzari 5 H. Michalik 27 Giampiero Naletto 28 Nilda Oklay 4 A. Pommerol 1 F. Preusker 23 F. Scholten 23 Cécilia Tubiana 4 Jean-Baptiste Vincent 4
Abstract : The OSIRIS camera onboard the Rosetta spacecraft has been acquiring images of the comet 67P/Churyumov-Gerasimenko (67P/C-G)’s nucleus at spatial resolutions down to ~0.17 m/px ever since Aug 2014. These images have yielded unprecedented insight into the morphological diversity of the comet’s surface. This paper presents an overview of the regional morphology of comet 67P/C-G. Methods. We used the images that were acquired at orbits ~20–30 km from the center of the comet to distinguish different regions on the surface and introduce the basic regional nomenclature adopted by all papers in this issue that address the comet’s morphology and surface processes. We used anaglyphs to detect subtle regional and topographical boundaries and images from close orbit (~10 km from the comet’s center) to investigate the fine texture of the surface. Results. Nineteen regions have currently been defined on the nucleus based on morphological and/or structural boundaries, and they can be grouped into distinctive region types. Consolidated, fractured regions are the most common region type. Some of these regions enclose smooth units that appear to settle in gravitational sinks or topographically low areas. Both comet lobes have a significant portion of their surface covered by a dusty coating that appears to be recently placed and shows signs of mobilization by aeolian- like processes. The dusty coatings cover most of the regions on the surface but are notably absent from a couple of irregular large depressions that show sharp contacts with their surroundings and talus-like deposits in their interiors, which suggests that short- term explosive activity may play a significant role in shaping the comet’s surface in addition to long-term sublimation loss. Finally, the presence of layered brittle units showing signs of mechanical failure predominantly in one of the comet’s lobes can indicate a compositional heterogeneity between the two lobes.
Type de document :
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Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A26 (28 p.). <10.1051/0004-6361/201525723>
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Soumis le : samedi 26 septembre 2015 - 10:53:48
Dernière modification le : lundi 29 mai 2017 - 15:02:03

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M.R. El-Maarry, Nicholas Thomas, L. Giacomini, M. Massironi, M. Pajola, et al.. Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images. Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A26 (28 p.). <10.1051/0004-6361/201525723>. <insu-01205653>

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