Asteroid-Asteroid Interactions - Dynamically Irrelevant?

Abstract

Structural investigations of the distribution of the asteroids have so far concentrated on the interactions with the major planets, especially Jupiter, and the resulting effects in element space. Here some less known structures of their distribution in actual space are shown: the radial number density and the orthogonal orbit density. A closer look at the orbit densities at different length scales reveals structures that are difficult to explain by gravitational influences from the major planets. This is particularly conspicious if special subgroups like the original Hirayama families are considered. A further limit for inter-asteroid-interactions comes from the distribution of locations of actual close encounters in space. A comparison with the gravitational cross section densities of the terrestrial planets and their influences on the population of planet crossing asteroids indicates that some interactions with the asteroids should lead to observable effects but the involved timescales are difficult to estimate because of the inhomogeneity of the asteroid distribution.