The PI and his team will carry out a theoretical effort to improve understanding of the interior, formation and evolution of ice- and gas-giant planets in our solar system and other extrasolar planetary systems. They will apply computer simulations techniques to study planetary interior materials exposed to extreme temperatures and pressures that cannot be reproduced in the laboratory. They will do this by simulating thermodynamic properties of the gases, such as the equation of state (EOS), which gives the mathematical relationship between temperature, pressure and density of a material. The investigators will apply their models to a collection of ice giant planets with masses less than that of Neptune. They also plan to develop a new model for Uranus' and Neptune's interior that includes a diamond layer, in order to explain these planets' peculiar magnetic fields. They will work with collaborators to prepare complementary high-pressure experiments, and to update models of Jupiter and Saturn. Computational results will be provided to the astronomical community for use in planetary and stellar interior models. They will also train graduate and undergraduate students in computational research techniques.
The investigators will accomplish this by incorporating the group's new ab initio Hydrogen-Helium EOS into existing code in order to model rotating giant planets. They will also update phase diagrams for liquid and superionic water and simulate the mixtures of water, methane and ammonia in these planets. They will use these results to improve evolutionary models of Jupiter and Saturn, and magnetic field models of Uranus and Neptune. They will also incorporate the EOS tables into the stellar evolution code MESA, and provide results to the community about ab initio Gibbs free energy calculations in solid, liquid, superionic and lower-density molecular systems.
