Collisional Fragmentation Experiments of Plaster Sphere at Low Velocities

Abstract

Physical processes of planetary formation from dusts to planetesimals are not well understood. A previous experiment on collisional response of water ice spheres showed that the critical velocity, which was the onset velocity of fracturing depends on the size of the sphere (Higa et al.1998).
Since aggregate of dusts have high porosity, we performed low velocity collision experiments of gypsum spheres of about 50% in porosity. We found that compaction occurred at lower velocities than those where fracturing occurred. We will discuss on the influence of compaction on the critical velocity.