Shape model, reference system definition, and cartographic mapping standards for comet 67P/Churyumov-Gerasimenko - Stereo-photogrammetric analysis of Rosetta/OSIRIS image data
Journal
Date Issued
2015
Author(s)
Preusker, F.
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Scholten, F.
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Matz, K. -D.
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Roatsch, T.
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Willner, K.
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Hviid, S. F.
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Knollenberg, J.
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Jorda, L.
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Gutiérrez, P. J.
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Kührt, E.
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Mottola, S.
•
A'Hearn, M. F.
•
Thomas, N.
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Sierks, H.
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Barbieri, C.
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Lamy, P.
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Rodrigo, R.
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Koschny, D.
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Rickman, H.
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Keller, H. U.
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Agarwal, J.
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Barucci, M. A.
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Bertaux, J. -L.
•
Bertini, I.
•
•
Da Deppo, V.
•
Davidsson, B.
•
Debei, S.
•
De Cecco, M.
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Fornasier, S.
•
•
Groussin, O.
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Güttler, C.
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Ip, W. -H.
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Kramm, J. R.
•
Küppers, M.
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Lara, L. M.
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Lazzarin, M.
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Lopez Moreno, J. J.
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Marzari, F.
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Michalik, H.
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Naletto, G.
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Oklay, N.
•
•
Vincent, J. -B.
Description
OSIRIS was built by a consortium of the Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany, CISAS – University of Padova, Italy, the Laboratoire d’Astrophysique de Marseille, France, the Instituto de Astrofísica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department 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 University, Sweden, and the Institut für Datentechnik und Kommunikationsnetze der Technischen Universität Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We finally thank Nat Bachman (JPL/NAIF) for his very helpful support in the preparation of SPICE planetary constants kernels and the consortium that developed the MeshLab processing system for making it freely available.
Abstract
We analyzed more than 200 OSIRIS NAC images with a pixel scale of 0.9-2.4 m/pixel of comet 67P/Churyumov-Gerasimenko (67P) that have been acquired from onboard the Rosetta spacecraft in August and September 2014 using stereo-photogrammetric methods (SPG). We derived improved spacecraft position and pointing data for the OSIRIS images and a high-resolution shape model that consists of about 16 million facets (2 m horizontal sampling) and a typical vertical accuracy at the decimeter scale. From this model, we derive a volume for the northern hemisphere of 9.35 km3 ± 0.1 km3. With the assumption of a homogeneous density distribution and taking into account the current uncertainty of the position of the comet's center-of-mass, we extrapolated this value to an overall volume of18.7 km3± 1.2 km3, and, with a current best estimate of 1.0 × 1013 kg for the mass, we derive a bulk density of 535 kg/m3± 35 kg/m3. Furthermore, we used SPG methods to analyze the rotational elements of 67P. The rotational period for August and September 2014 was determined to be 12.4041 ± 0.0004 h. For the orientation of the rotational axis (z-axis of the body-fixed reference frame) we derived a precession model with a half-cone angle of 0.14°, a cone center position at 69.54°/64.11° (RA/Dec J2000 equatorial coordinates), and a precession period of 10.7 days. For the definition of zero longitude (x-axis orientation), we finally selected the boulder-like Cheops feature on the big lobe of 67P and fixed its spherical coordinates to 142.35° right-hand-rule eastern longitude and -0.28° latitude. This completes the definition of the new Cheops reference frame for 67P. Finally, we defined cartographic mapping standards for common use and combined analyses of scientific results that have been obtained not only within the OSIRIS team, but also within other groups of the Rosetta mission.
Appendices are available in electronic form at http://www.aanda.org
Volume
583
Start page
A33
Issn Identifier
0004-6361
Ads BibCode
2015A&A...583A..33P
Rights
open.access
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