Asteroidal catastrophic collisions simulated by hypervelocity impact experiments

Catastrophic collisions have played an important part in the evolution of asteroids and small natural satellites, and an understanding of such processes is essential. The present paper provides a description of a set of impact experiments carried out at a velocity of about 9 km/sec, taking into account the use of an experimental technique which allows projectiles with mass of the order of 1 g to be accelerated routinely up to 10 km/sec. Attention is given to the experimental procedure, the mass distribution of fragments, fragment shapes, the geometrical characteristics of the breakup phenomenon, and the ejecta. The fragment mass distributions show clearly the importance of the impact geometry, possibly enhanced by some focusing of the impact-generated shock waves, in determining the degree of target fragmentation. The fragment shapes are in good agreement with the shapes of main-belt asteroids less than 100 km across. 31 references