Collisional evolution of Trans-Neptunian populations: Effects of fragmentation physics and estimates of the abundances of gravitational aggregates

The Trans-Neptunian region is yet another example of a collisional system of small bodies in the Solar System. In the last decade the number of TNOs with reliable orbital elements is steadily increasing and even if it is still premature to compare models with observations, we can start to have some idea of the orbital structure and magnitude distribution, so that some loose constraints may be set on the critical parameters that affect collisional evolution. With this aim we have developed a model for the collisional evolution of the Trans-Neptunian region by dividing it into three main different populations, corresponding to the dynamical classification proposed by Gladman et al. [2001.The structure of the Kuiper Belt: size distribution and radial extent. Astrophys. J. 122, 1051] (Resonant region, Classical Belt and Scattered Disk). A multi-zone collisional model is developed, in which each zone can collisionally interact with each other. The model takes into account the known physics of the fragmentation of icy/rocky bodies at the typical relative velocities of TNOs, according to velocity distributions corresponding to each evolving zone. The dependence of the evolution of the considered populations on physically critical collisional parameters is investigated and the corresponding results are presented, including estimates of the abundance of gravitational aggregates in the studied populations.