P. Sánchez¹ and D. J. Scheeres²

¹Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado, USA
²Engineering Sciences Colorado, The Center for Astrodynamics Research, The University of Colorado at Boulder, Boulder, Colorado, USA

We explore the hypothesis that, due to small van der Waals forces between constituent grains, small rubble pile asteroids have a small but nonzero cohesive strength. The nature of this model predicts that the cohesive strength should be constant independent of asteroid size, which creates a scale dependence with relative strength increasing as size decreases. This model counters classical theory that rubble pile asteroids should behave as scale-independent cohesionless collections of rocks. We explore a simple model for asteroid strength that is based on these weak forces, validate it through granular mechanics simulations and comparisons with properties of lunar regolith, and then explore its implications and ability to explain and predict observed properties of small asteroids in the NEA and Main Belt populations, and in particular of asteroid 2008 TC₃. One conclusion is that the population of rapidly rotating asteroids could consist of both distributions of smaller grains (i.e., rubble piles) and of monolithic boulders.

Reference
Sánchez P and Scheeres DJ (in press) The strength of regolith and rubble pile asteroids. Meteoritics & Planetary Science
[doi:10.1111/maps.12293]
Published by arrangement with John Wiley & Sons

Link to Article