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Tidal disruption of Phobos as the cause of surface fractures
Author(s) -
Hurford T. A.,
Asphaug E.,
Spitale J. N.,
Hemingway D.,
Rhoden A. R.,
Henning W. G.,
Bills B. G.,
Kattenhorn S. A.,
Walker M.
Publication year - 2016
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2015je004943
Subject(s) - mars exploration program , geology , regolith , astrobiology , tidal heating , tidal force , geophysics , astronomy , physics , planet
Abstract Phobos, the innermost satellite of Mars, displays an extensive system of grooves that are mostly symmetric about its sub‐Mars point. Phobos is steadily spiraling inward due to the tides it raises on Mars lagging behind Phobos' orbital position and will suffer tidal disruption before colliding with Mars in a few tens of millions of years. We calculate the surface stress field of the deorbiting satellite and show that the first signs of tidal disruption are already present on its surface. Most of Phobos' prominent grooves have an excellent correlation with computed stress orientations. The model requires a weak interior that has very low rigidity on the tidal evolution time scale, overlain by an ~10–100 m exterior shell that has elastic properties similar to lunar regolith as described by Horvath et al. (1980).