Collisional Effects in the Edgeworth-Kuiper Belt

Abstract

The Edgeworth—Kuiper (E—K) belt, a population of small bodies a thousand times greater in number than that of the main asteroid belt orbiting outside Neptune’s orbit, is undergoing collisional comminution. The discovery of these bodies confirmed strong dynamical evidence that short period comets come from a transneptunian source region. Like main belt asteroids, the size distribution of E—K belt objects has been affected by mutual impacts over Solar System history. Collisional evolution studies of the E-K belt show that bodies larger than several tens of km in diameter survive over times comparable to the age of the Solar System, hence their size distribution reflects accretionary processes in the early Solar System. At smaller sizes, however, impacts have produced a collisionally relaxed population of fragments which are predicted to have a power-law size distribution with an incremental diameter exponent near −3.5. Collisions can also inject km-sized fragments into dynamical resonances, whence they can be transported to the inner Solar System to become short period comets. However, dynamical mechanisms are needed to produce the Centaurs, a population of much larger bodies than the Jupiter family comets.