Fig. 13

Schematic of the possible structure of rubble pile asteroids. The original reaccretion of these objects is assumed to be particle size sorted with the largest pieces accreting first to form the core of the object and successively smaller sizes accreting later (Michel and Richardson 2013). The finest size fractions are generated at the surface by regolith action. These fine particles are confined to the near-surface zone by the dominance of frictional forces (from Britt and Consolmagno 2001)