event
Wednesday 15 Feb 2012: A Planetesimal Pas de Deux or the Clash of the Titans: A Model for Collisions in Planet Formation
Dr Zoe Leinhardt - University of Bristol
Physics, 4th floor 14:00-14:45
Collisions are the core component of planet formation. The range of impact parameters encountered during growth from planetesimals to planets span multiple collision outcome regimes: cratering, merging, disruption, and hit-and-run events. Because of the range of collision outcome and variations in the material properties of planetary bodies, no general set of equations exist to capture the basic physics of collisions. At present, collision outcomes in planet formation simulations are applicable only to a specific subset of possible collision parameters. Using new high-resolution simulations of collisions between planetesimals for a wide range of impact parameters we have derived a complete analytic description of the dynamical outcome for any collision between gravity-dominated bodies (100 m planetesimals to planets). We then apply our new model to published results of the stochastic end stage of planet formation. We find that our predicted timescale of planet formation is significantly increased, mass and volatile content of the planets is reduced, and the diversity of resulting planets is significantly changed by our collision outcome model. It is clear from this work that more realistic modelling of planetesimal evolution is required if we are to understand the prolific production of planets in detail.
