Planetary Accretion
The manner in which the planets were initially put together probably controls their subsequent evolution. We have two ways of investigating the accretion process: numerical models; and geochemical observations. My interest is in combining these two approaches to get better constraints on how the terrestrial planets actually form. To do this I work with Craig Agnor (UCSC), who is an expert in numerical accretion simulations. A particularly important part of the planetary formation process is the separation of the core from the mantle. This differentiation process has a large effect on the subsequent history of the core, and in the case of Mars may have determined the lifetime of the dynamo.
Figure 1. Example accretion history of a Mars-sized object. Note the two collisions (at 1.5 and 3 Myr) with similarly-sized bodies.
Publications
Here is a list of accretion-related topics I have published or submitted:
Isotopic outcomes of N-body accretion simulations: Constraints on equilibration processes during large impacts from Hf/W observations, F. Nimmo and C.B. Agnor, Earth Planet. Sci. Lett. , 243, 26-43, 2006. Reprint (PDF)
Thermal evolution of the Martian core:
Implications for an early dynamo, J.-P. Williams and F. Nimmo, Geology , 32(2), 97-100, 2004. Reprint
,
Thermal and Compositional Evolution of the Core F. Nimmo, Treatise on Geophysics (G. Schubert, ed.), submitted. Preprint (PDF)
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