Impact modeling of Kuiper Belt objects

Abstract

The solar system's Kuiper belt is likely to contain many objects similar in size to Pluto. Pluto's composition, based on its mean density (2030 kg/m3), is 60% rock and 40% ice. This composition is notably more rich in rock than typical outer solar system satellites, which have rock fractions of 40%. This work investigates the possibility that devolatilization (the removal of ice) of typical Kuiper Belt Objects (KBOs) may occur as a byproduct of large impacts. Our target KBO is represented as an object with a 40% rock mass fraction. The impactor is a cometary object composed entirely of ice. We model the collision of the target with a series of impactors, varying the impactor's size and angle. These impacts are simulated using a three-dimensional smoothed-particle hydrodynamics (SPH) code. For each impact, we analyze the fraction of ice thrown off from the target. The impact speed is the escape speed of the target object (-1.5 km/s). Our simulations will constrain the cricital impactor size and impact angle ranges required to increase the final rock mass fraction of the target to the 60% value observed for Pluto.