Preliminary speculation on accretion mechanism associated with 'Rubble Pile' celestial objects

Abstract

Itokawa visited by Hayabusa belongs to the 'Rubble Pile' category, which accumulated fragments that derived from the collision between larger celestial bodies. Here is left a simple question as to the formation process. It is on whether Itokawa's shape is a typical Rubble Pile shape. The asteroids so far visited have shown different shapes and the answer to it apparently seems incorrect. However, the paper will look into the accretion and evolution process about such irregular shaped bodies, and tries to present a certain, but still preliminary, evolution mechanism and stories, by which the Itokawa's shape may tell us some typical evolution history. Show more