Dynamics and Evolution of Earth-like Planets

Coordinators: Eric Ford, Louise Kellogg, Geoff Marcy, Burkhard Militzer

Scientific Advisors: Russell Hemley, Barbara Romanowicz

The discovery of rocky planets beyond the solar system is rapidly expanding the scope of traditional interior geophysics.   The diverse interiors, atmospheres with varying amounts of gas and volatile elements, and potential oceans on such planets spawn broader questions about their formation, including the physics of protoplanetary disks, the accumulation of refractory material, the dynamical interactions of embryonic rocky bodies and gas, and the build-up of rocky planets with associated lighter material.   New astronomical observations, such as measurements of radii and masses of nearly Earth-size planets, transit-timing variations, orbital resonances, the Rossiter-McLaughlin effect, and the frequency of planets as a function of size, orbital properties, and stellar host properties, are now informing the physics of planet formation and providing the boundary conditions that constrain the ultimate interior structures of rocky planets.  The range of interior structures of Earth-size and super-Earth-size planets must be understood in terms of the diverse physics and chemistry of their formation history.  Recent advances in understanding the properties of minerals at elevated pressures and temperatures provide essential constraints on the thermodynamics and rheology of planetary interiors. Similarly, advances in computational methods and capabilities are enabling simulation of the dynamical processes governing planetary interiors of exoplanets.  This program is intended to synthesize recent advances from astrophysics and geophysics to advance the theory of the composition, structure, and dynamics of rocky planets.