Fragmentation of colliding planetesimals with water content

TL;DR

This study models collisions of water-rich, Ceres-sized planetesimals using advanced mechanics to understand fragmentation, water transfer, and outcomes relevant to planetary formation and asteroid family evolution.

Contribution

It introduces a novel simulation approach incorporating full elasto-plastic mechanics for water-rich bodies, improving understanding of collision outcomes and water distribution.

Findings

Fragmentation patterns depend on impact velocity and angle.

Water content distribution varies with collision parameters.

Results inform planetary formation and asteroid family models.

Abstract

We investigate the outcome of collisions of Ceres-sized planetesimals composed of a rocky core and a shell of water ice. These collisions are not only relevant for explaining the formation of planetary embryos in early planetary systems, but also provide insight into the formation of asteroid families and possible water transport via colliding small bodies. Earlier studies show characteristic collision velocities exceeding the bodies' mutual escape velocity which - along with the distribution of the impact angles - cover the collision outcome regimes 'partial accretion', 'erosion', and 'hit-and-run' leading to different expected fragmentation scenarios. Existing collision simulations use bodies composed of strengthless material; we study the distribution of fragments and their water contents considering the full elasto-plastic continuum mechanics equations also including brittle failure and fragmentation.