Universität zu Köln

Guo, Xi, Yan, Jianguo, Andert, Tom, Yang, Xuan, Paetzold, Martin, Hahn, Matthias, Ye, Mao, Liu, Shanhong, Li, Fei and Barriot, Jean-Pierre (2021). A lighter core for Phobos? Astron. Astrophys., 651. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The origin of the Martian moons Phobos and Deimos is still poorly understood, and is the focus of intense debate.Aims. We demonstrate that a stratified internal structure of Phobos is compatible with the observed gravity coefficients.Methods. We fit previously derived C-20 and C-22 Phobos gravity coefficients derived from the combined MEX Doppler-tracking data from the close flybys in +2010 and 2013 with respect to the corresponding coefficients of a core-mantle stratification model of Phobos, with two opposite cases: a core denser than the mantle, and a core lighter than the mantle.Results. Only the case with a core lighter than the mantle fits at the 3 sigma level the previously reported observed second degree and order coefficient C-20, but a homogeneous Phobos cannot be strictly ruled out at the 3 sigma level.Conclusions. This possible loosening of the core density might be the result of a displacement of material toward the surface, may be caused by centrifugal forces acting on a loosely packed rubble-pile structure, and/or by a hot-then-cold in-orbit accretion process. These two hypotheses are by no means exhaustive.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Guo, Xi UNSPECIFIED UNSPECIFIED UNSPECIFIED Yan, Jianguo UNSPECIFIED UNSPECIFIED UNSPECIFIED Andert, Tom UNSPECIFIED UNSPECIFIED UNSPECIFIED Yang, Xuan UNSPECIFIED UNSPECIFIED UNSPECIFIED Paetzold, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Hahn, Matthias UNSPECIFIED UNSPECIFIED UNSPECIFIED Ye, Mao UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Shanhong UNSPECIFIED UNSPECIFIED UNSPECIFIED Li, Fei UNSPECIFIED UNSPECIFIED UNSPECIFIED Barriot, Jean-Pierre UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-581222
DOI:	10.1051/0004-6361/202038844
Journal or Publication Title:	Astron. Astrophys.
Volume:	651
Date:	2021
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GRAVITATIONAL-FIELD; GRAVITY-FIELD; MARS EXPRESS; TAGISH LAKE; MASS; COEFFICIENTS; METEORITE; POROSITY; MODELS; FLYBY Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58122