Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Geophysical Research Letters Year : 2015

Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

L. Jorda
Jean-Loup Bertaux

Abstract

The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.
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Dates and versions

insu-01176074 , version 1 (11-07-2020)

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M.R. El-Maarry, N. Thomas, A. Gracia-Berná, R. Marschall, A-T. Auger, et al.. Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS. Geophysical Research Letters, 2015, 42 (13), pp.5170-5178. ⟨10.1002/2015GL064500⟩. ⟨insu-01176074⟩
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