Formes d'ast\'ero\"ides et formation de satellites : r\^ole de la r\'eaccumulation gravitationnelle

TL;DR

This study uses N-body simulations to explore how gravitational reaccumulation during asteroid formation influences their shapes and satellite formation, revealing that flattened spheroids are a common outcome.

Contribution

It demonstrates that gravitational reaccumulation can produce specific asteroid shapes, especially flattened spheroids, providing insights into asteroid evolution and satellite formation.

Findings

Only flattened spheroids are formed through this mechanism

Simulations match theoretical predictions of shape and rotation

Results suggest shape constraints for asteroid evolution

Abstract

Asteroid shapes and satellites: role of gravitational reaccumulation. Following current evidences, it is widely accepted that many asteroids would be "gravitational aggregates", i.e. bodies lacking internal cohesion. They could mainly be originated during the catastrophic disruption of some parent bodies, through the gravitational reaccumulation 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 inhelastic 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.