THERMODYNAMIC EVOLUTION OF PLANETESIMALS IN THE PRIMORDIAL EDGEWORTH- KUIPER BELT INDUCED BY COLLISIONS

Introduction: The Kuiper Belt Objects (hereafter KBOs) and cometary nuclei are considered to be among the most primordial objects of the outer solar system. However, 90% of the mass of the Kuiper belt was lost through collisions and ejections by dynamical interactions with Neptune [1-2]. Most of the small bodies that have survived in this collisonnal environment have certainly been physically damaged by multiple collisions. Thus, the population of comet-sized objects has been greatly eroded [3]. Cometary nuclei could then be derived from larger parent body [4-5]. Due to the heating generated by collisions during this period, and since they might have experienced some physicochemical differentiation, the composition of these bodies might not reflect that of the primordial planetesimals. Here, we investigate the post-impact thermochemical evolution of comet-size objects and larger parent bodies located in the outer solar system.