Wednesday 16 Nov 2016: Getting to the core of terrestrial planet formation
Dr. Philip Carter - University of Bristol
Physics, 4th Floor 15:30-16:30
Models of planet formation help bridge the observational gap between protoplanetary discs and fully formed planetary systems. Our solar system provides key benchmarks for planet formation theories, particularly via detailed compositional information both from the Sun and from meteorites. We can study planetary evolution by examining the deviation of observed planetary compositions from the composition of primitive meteorites. The Earth appears to be non-chondritic in its abundances of refractory elements, posing a significant problem for our understanding of its formation and evolution. I will present the results of N-body simulations of terrestrial planet formation that include a state-of-the-art collision model and track the core mass fraction of the growing planetary embryos. I will show that the accretion process during the runaway and oligarchic growth phases can naturally lead to a change in the bulk composition of the final embryos. With significant dynamical excitation enough mantle can be stripped from growing embryos to account for the Earth's non-chondritic Fe/Mg ratio.