DIX Planetary Science Seminar

How and when the Solar System's planets and satellites formed is a fundamental problem in planetary sciences, and one that has few observational constraints. For the inner solar system, one such constraint is provided by the Hf-W isotopic system, which can be used as a chronometer. I will argue that this isotopic system can be used to test different models of terrestrial planet accretion (such as the "Grand Tack"), and investigate different scenarios for the formation of the Moon. In the outer solar system, isotopic measurements are made by in situ analysis or spectroscopy. I discuss a model for the formation of the satellites of Jupiter which predicts oxygen and D/H isotopic anomalies. This model, which invokes hydrodynamic escape during accretion, explains the observed trend in bulk composition; the isotopic predictions will be tested with the forthcoming Europa Clipper and JUICE missions.