Bremen 2017 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 12: Planeten und kleine Körper II
EP 12.1: Hauptvortrag
Donnerstag, 16. März 2017, 15:00–15:30, GW2 B2880
The Gravity Field of 67P/Churyumov-Gerasimenko from the Rosetta Radio Science Experiment — Martin Pätzold1, •Matthias Hahn1, Tom Andert2, Sami Asmar3, Jean-Pierre Barriot4, Michael Bird1, Bernd Häusler2, Kerstin Peter1, Silvia Tellmann1, Eberhard Grün5, and Paul Weissman3 — 1Rheinisches Institut für Umweltforschung an der Universität zu Köln, Cologne, Germany — 2Universität der Bundeswehr München, Neubiberg, Germany — 3Jet Propulsion Laboratory, Caltech, Pasadena, CA, USA — 4Universite de la Polynesie Francaise, Faaa, Tahiti — 5MPI für Kernphysik, Heidelberg, Germany
The Rosetta spacecraft arrived at its target comet 67P/Churyumov-Gerasimenko in August 2014. The distance to the comet was gradually lowered from 100 to less than 10 km. The mass and the low degree and order gravity field of the nucleus could be determined. That gave insights into the comets interior structure. The nucleus appears to be a low-density, highly porous dusty body. The spacecraft escorted the comet through its perihelion. Strong outgassing pressure forced the spacecraft to remain at relatively large distances. When the comets activity decreased again after perihelion a second determination of its mass and gravity field was possible. The total mass loss due to outgassing could be measured. Using spherical harmonic functions to describe the nucleus gravity field is difficult because of its highly irregular shape. A new technique using a bipolar approach provides a better representation of the nucleus gravity especially at low orbital distances. It was possible to distinguish densities of the two main lobes.