Article Dans Une Revue Nature Geoscience Année : 2019

Bilobate comet morphology and internal structure controlled by shear deformation

1 CEREGE - Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement
2 LAM - Laboratoire d'Astrophysique de Marseille
3 Faculty of Natural Sciences [Stirling]
4 DLR Institut für Planetenforschung
5 GEOPS - Géosciences Paris Sud
6 PLANETO - LATMOS
7 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
8 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
9 Dipartimento di Fisica e Astronomia "Galileo Galilei"
10 IFN - CNR Istituto di Fotonica e Nanotecnologie [Padova]
11 IAA-CSIC - Instituto de Astrofísica de Andalucía = Institute of Astrophysics of Andalusia
12 ISSI - International Space Science Institute [Bern]
13 RSSD - Research and Scientific Support Department, ESTEC
14 JPL - Jet Propulsion Laboratory
15 LESIA (UMR_8109) - Laboratoire d'études spatiales et d'instrumentation en astrophysique
16 Department of Physics [Auburn]
17 OAPD - INAF - Osservatorio Astronomico di Padova
18 IFN - CNR Institute for Photonics and Nanotechnologies
19 Department of Industrial Engineering [University of Padua]
20 UNITN - Università degli Studi di Trento = University of Trento
21 OAT - INAF - Osservatorio Astronomico di Trieste
22 Institute of Space Science [Taiwan]
23 IANCU - Institute of Astronomy [Taiwan]
24 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
25 Dipartimento di Geoscienze [Padova]
26 Department of Physics and Astronomy [Uppsala]
27 Konkoly Observatory
L. Jorda
S. Bouley
Jean-Loup Bertaux
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I. Toth
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Résumé

Bilobate comets-small icy bodies with two distinct lobes-are a common configuration among comets, but the factors shaping these bodies are largely unknown. Cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the Sun, but the importance of a comet's internal structure on its erosion is unclear. Here we present three-dimensional analyses of images from the Rosetta mission to illuminate the process that shaped the Jupiter-family bilobate comet 67P/Churyumov-Gerasimenko over billions of years. We show that the comet's surface and interior exhibit shear-fracture and fault networks, on spatial scales of tens to hundreds of metres. Fractures propagate up to 500 m below the surface through a mechanically homogeneous material. Through fracture network analysis and stress modelling, we show that shear deformation generates fracture networks that control mechanical surface erosion, particularly in the strongly marked neck trough of 67P/Churyumov-Gerasimenko, exposing its interior. We conclude that shear deformation shapes and structures the surface and interior of bilobate comets, particularly in the outer Solar System where water ice sublimation is negligible.

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Dates et versions

hal-02087743 , version 1 (02-10-2025)

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C. Matonti, N. Attree, O. Groussin, L. Jorda, S. F. Hviid, et al.. Bilobate comet morphology and internal structure controlled by shear deformation. Nature Geoscience, 2019, 12 (3), pp.157-162. ⟨10.1038/s41561-019-0307-9⟩. ⟨hal-02087743⟩
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