Collisional origin of asteroid families - Effects of the target's gravity

The outcomes of asteroidal catastrophic collisions are strongly affected by the target asteroid's gravity, since only the fragments escaping with initial velocities higher than the target's escape velocity are not reaccumulated into 'rubble pile' remnants. This idea can be compared with the observational evidence on the properties of family asteroids in several ways: (1) the shape and spin period of the 'reaccumulated' family asteroids will roughly fit the relationships valid for self-gravitating fluid bodies; (2) the relative velocities of the few escaping fragments arising from a breakup event marginally overcoming self-gravity will often have an anisotropic distribution, affecting the final distribution of orbital elements; and (3) the amount of mass which in a given family escaped to 'infinity' will be correlated with the target's size, since only for objects larger than approximately 100 km self-gravity plays an important role. These predictions are discussed and compared with the available data.