The Shape of Comet 67P/Churyumov-Gerasimenko from Rosetta/Osiris Images

Thursday, 18 December 2014
Laurent Jorda1, Robert W Gaskell2, Stubbe F Hviid3, Claire Capanna1, Olivier Groussin1, Pedro GutiƩrrez4, Lamy Philippe1, Frank Scholten3, Frank Preusker3, Horst Uwe Keller5, Knollenberg Joerg3, Ekkehard Kuhrt3, Stefano Mottola3, Holger Sierks6, Colin Snodgrass6, Nicolas Thomas7, Jean-Baptiste Vincent6, Simone Marchi8 and Matteo Massironi9, (1)Laboratoire d'Astrophysique de Marseille, Marseille, France, (2)Planetary Science Institute Tucson, Tucson, AZ, United States, (3)German Aerospace Center (DLR), Berlin, Germany, (4)Instituto de Astrofisica de Andalucia, Granada, Spain, (5)Technical University of Braunschweig, Braunschweig, Germany, (6)Max-Planck Institute for Solar System Research, Goettingen, Germany, (7)University of Bern, Bern, Switzerland, (8)NASA Lunar Science Institute, Boulder, CO, United States, (9)Univ Padova, Padova, Italy
The ROSETTA mission has reached the nucleus of comet 67P/Churyumov-Gerasimenko in early August, allowing a detailed mapping of its surface with the onboard OSIRIS imaging system, up to resolutions of 50 cm or even better in some areas. Shape reconstruction techniques have been used since July 2014 to build a very detailed 3D model of the comet surface and to retrieve highly accurate rotational parameters. The attached Figure shows an early 3D shape of the comet.

The most striking property of the global shape is the presence of two clearly separated components. We use a combination of images and 3D models to quantitatively characterize their bulk and surface properties: relative position, volume, topography and roughness. The position of the center of mass and the direction of the principal axis of rotation are used to constrain the internal mass distribution. Digital terrain models, slope, gravity, and geo-referenced images of the most interesting features observed at the surface of the comet are presented and consequences for their formation are discussed. If they are detected, topographic changes which could have occured between August and December 2014 are also presented.

Acknowledgements. OSIRIS was built by a consortium led by the Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofísica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Técnica Aeroespacial, Madrid, Spain, the Universidad Politéchnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala