This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This project will investigate the gas dynamics of protoplanetary disks, and the interaction of disks with planets. The work includes (1) studies of angular momentum transport by the magnetorotational instability (MRI) in protoplanetary disks, (2) studies of the propagation and damping of, and gap opening by, density waves excited by disk-planet interaction, and (3) fully global models of protoplanetary disks that can investigate the structure and evolution of disks over a wide range of radii. Realistic models of protoplanetary disks are challenging because of the diverse range of physics that must be included, and these calculations will be the most sophisticated yet attempted. These simulations will follow the turbulent mixing and settling of dust grains in the disk self-consistently with the gas dynamics by integrating the motion of millions of particles drawn from a realistic size distribution. Effects to be added are recombination on grains, as part of a twelve-species non-equilibrium ionization and recombination network, all of the relevant non-ideal magnetohydrodynamic (MHD) processes, and radiative diffusion and optically thin cooling to follow the thermodynamics of the gas. All of the necessary code elements have been implemented and tested within Athena, a new and powerful grid-based code for astrophysical MHD. The result should be the most realistic and accurate models of the non-ideal MHD of protoplanetary disks possible, and a deep understanding of the environment of planet formation and the interaction of planets with the disk.
The project includes training of graduate students, and animations and visualizations for dissemination of the results to the wider public. The team is vigorously engaged in involving women and under-represented groups in theoretical and computational astrophysics through a Princeton summer undergraduate research program. The work continues to foster interdepartmental and international collaboration by providing access to the Athena code to the astrophysics community through an open-source software philosophy.
