Dynamical evolution of the inner asteroid belt

A determination of the dynamical evolution asteroid belt is difficult because has evolved since time formation through mechanisms that include: (1) catastrophic collisions, (2) rotational disruption, (3) chaotic orbital and (4) driven by Yarkovsky radiation forces. The timescales these loss are uncertain there a need for more observational constraints. In inner main belt, mean size non-family asteroids increases with increasing inclination. Here, we use observation to show all originate from either known families or ghost families, is, old dispersed elements. We estimate average age in factor 1/3 less than timescale. However, this timescale long-term must allow collisional stochastic changes their spin directions. By applying constraints on size-frequency distribution Vesta family, family greater 1.3 $Gyr$ could be comparable solar system. estimating number calculate root sources meteorites near-Earth about 20.