title: COMETARY SCIENCE. Properties of the 67P/Churyumov-Gerasimenko interior revealed by CONSERT radar.
abstract: The Philae lander provides a unique opportunity to investigate the internal structure of a comet nucleus, providing information about its formation and evolution in the early solar system. We present Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) measurements of the interior of Comet 67P/Churyumov-Gerasimenko. From the propagation time and form of the signals, the upper part of the "head" of 67P is fairly homogeneous on a spatial scale of tens of meters. CONSERT also reduced the size of the uncertainty of Philae's final landing site down to approximately 21 by 34 square meters. The average permittivity is about 1.27, suggesting that this region has a volumetric dust/ice ratio of 0.4 to 2.6 and a porosity of 75 to 85%. The dust component may be comparable to that of carbonaceous chondrites.
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Wlodek
authors.initials: W
authors.lastname: Kofman
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Herique
authors.affiliation: MIO, UM 110, CNRS-Institut National des Sciences de l'Univers (INSU), Université de Toulon, Aix-Marseille Université, IRD 83957 La Garde, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Barbin
authors.affiliation: Geodesy Observatory of Tahiti BP6570, 98702 Faa'a, Tahiti.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Barriot
authors.affiliation: Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) (UPSay); Université Pierre et Marie Curie (UPMC) (Sorbonne Univ.); CNRS/INSU; Laboratoire Atmosphéres, Milieux, Observations Spatiales (LATMOS)-Institut Pierre-Simon Laplace (IPSL), 11 Boulevard d'Alembert, 78280 Guyancourt, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Ciarletti
authors.affiliation: Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Clifford
authors.affiliation: Ruhr-University of Bochum, Faculty of Electrical Engineering and Information Technology, 44780 Bochum, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Edenhofer
authors.affiliation: Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 300-243E, Pasadena, CA 91109, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Elachi
authors.affiliation: Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, 13013 Marseille, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Eyraud
authors.affiliation: Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) (UPSay); Université Pierre et Marie Curie (UPMC) (Sorbonne Univ.); CNRS/INSU; Laboratoire Atmosphéres, Milieux, Observations Spatiales (LATMOS)-Institut Pierre-Simon Laplace (IPSL), 11 Boulevard d'Alembert, 78280 Guyancourt, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Goutail
authors.affiliation: Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 300-243E, Pasadena, CA 91109, USA. University of Southern California, Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, Los Angeles, CA 90089, USA.
authors.forename: Essam
authors.initials: E
authors.lastname: Heggy
authors.affiliation: Laboratoire d'Astrophysique de Marseille Pôle de l'Étoile Site de Château-Gombert 38, Rue Frédéric Joliot-Curie 13388 Marseille, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Jorda
authors.affiliation: Université de Toulouse; UPS-OMP; IRAP; (2) CNRS; IRAP; 9 Avenue Colonel Roche, BP 44 346, F-31028 Toulouse Cedex 4, Toulouse, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Lasue
authors.affiliation: UPMC (Sorbonne Univ.); UVSQ (UPSay); CNRS/INSU; LATMOS-IPSL, BC 102, 4 place Jussieu, 75005 Paris, France.
authors.forename: Anny-Chantal
authors.initials: AC
authors.lastname: Levasseur-Regourd
authors.affiliation: Max-Planck-Institüt fur Sonnensystemforschung (MPS), Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany.
authors.forename: Erling
authors.initials: E
authors.lastname: Nielsen
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Pasquero
authors.affiliation: German Aerospace Center (DLR) Rutherfordstraße 2 12489 Berlin, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Preusker
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Puget
authors.affiliation: Technische Universitaet Dresden Helmholtzstraße 10 D-01069 Dresden, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Plettemeier
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Rogez
authors.affiliation: Max-Planck-Institüt fur Sonnensystemforschung (MPS), Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Sierks
authors.affiliation: Technische Universitaet Dresden Helmholtzstraße 10 D-01069 Dresden, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Statz
authors.affiliation: European Space Agency (ESA)/European Space Research and Technology Centre (ESTEC) Noordwijk, Netherlands.
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authors.lastname: Svedhem
authors.affiliation: Queen Mary University of London, Mile End Road, London E1 4NS, UK.
authors.forename: Iwan
authors.initials: I
authors.lastname: Williams
authors.affiliation: Université Grenoble Alpes, IPAG, F-38000 Grenoble, France (2) Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Zine
authors.affiliation: Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 300-243E, Pasadena, CA 91109, USA.
authors.forename: Jakob
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authors.lastname: Van Zyl