Plusieurs indices suggèrent qu'un grand nombre d'astéroïdes seraient des empilements de gravats, liés uniquement par gravité et quasiment dépourvus de cohésion interne. Leur formation serait due à la réaccumulation de fragments issus de la destruction antérieure d'un corps parent. La forme de ces objets, que l'on observe, pourrait ainsi être liée à ce processus de réaccumulation gravitationnelle. Toutefois, à l'heure actuelle, on ignore si les formes observées des astéroïdes sont le résultat de la seule réaccumulation ou d'événements ultérieurs entrainant un réajustement de la forme du corps.
Dans cette Note, nous nous interrogeons sur l'origine des formes des astéroïdes. A l'aide d'une étude numérique de la réaccumulation, nous étudions les formes d'équilibres possibles correspondants aux modèles théoriques. Les résultats montrent, pour la première fois, que seulement une catégorie précise de formes (sphéroïdes aplatis) est apparemment crée via ce mécanisme. Ces résultats pourraient ainsi fournir d'interessantes contraintes sur l'évolution des formes d'astéroïdes, notamment pour ceux possédant un, ou plusieurs, satellites.
Following current evidence, it is widely accepted that many asteroids would be ‘gravitational aggregates’, i.e. bodies lacking internal cohesion. They could mainly originate from the catastrophic disruption of some parent body, through the gravitational re-accumulation of the resulting fragments. The same events produced the dynamical families that we observe. In this work we address the problem of the origin of shapes of gravitational aggregates, that could contain signatures of their origin. We use a N-body code to simulate the collapse of a cloud of fragments, with a variety of initial velocity distributions and total angular momentum. The fragments are treated as inelastic spheres, that rapidly accumulate to form rotating aggregates. The resulting shapes and rotational properties are compared with theoretical predictions. The results show that only a precise category of shapes (flattened spheroids) are created via this mechanism. This may provide interesting constraints on the evolution of asteroid shapes, in particular for those with one or more satellites.
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Keywords: Solar System, Asteroids, Satellites, Collisions
@article{CRPHYS_2007__8_3-4_469_0,
author = {Jean-Fran\c{c}ois Consigli and Paolo Tanga and Carlo Comito and Daniel Hestroffer and Derek C. Richardson},
title = {Formes d'ast\'ero{\"\i}des et formation de satellites : r\^ole de la r\'eaccumulation gravitationnelle},
journal = {Comptes Rendus. Physique},
pages = {469--480},
publisher = {Elsevier},
volume = {8},
number = {3-4},
year = {2007},
doi = {10.1016/j.crhy.2007.02.006},
language = {fr},
}
TY - JOUR AU - Jean-François Consigli AU - Paolo Tanga AU - Carlo Comito AU - Daniel Hestroffer AU - Derek C. Richardson TI - Formes d'astéroïdes et formation de satellites : rôle de la réaccumulation gravitationnelle JO - Comptes Rendus. Physique PY - 2007 SP - 469 EP - 480 VL - 8 IS - 3-4 PB - Elsevier DO - 10.1016/j.crhy.2007.02.006 LA - fr ID - CRPHYS_2007__8_3-4_469_0 ER -
%0 Journal Article %A Jean-François Consigli %A Paolo Tanga %A Carlo Comito %A Daniel Hestroffer %A Derek C. Richardson %T Formes d'astéroïdes et formation de satellites : rôle de la réaccumulation gravitationnelle %J Comptes Rendus. Physique %D 2007 %P 469-480 %V 8 %N 3-4 %I Elsevier %R 10.1016/j.crhy.2007.02.006 %G fr %F CRPHYS_2007__8_3-4_469_0
Jean-François Consigli; Paolo Tanga; Carlo Comito; Daniel Hestroffer; Derek C. Richardson. Formes d'astéroïdes et formation de satellites : rôle de la réaccumulation gravitationnelle. Comptes Rendus. Physique, Volume 8 (2007) no. 3-4, pp. 469-480. doi : 10.1016/j.crhy.2007.02.006. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2007.02.006/
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