Institute for Advanced Study Informal Astrophysics Seminar

ABSTRACT: Abstract: The interaction between young planets and the gaseous protoplanetary disks from which they form leads to planet migration, gas accretion, and gap opening, each of which can significantly affect exoplanet demographics. Although most previous studies model the gas as a highly viscous disk, in reality protoplanetary disks are nearly inviscid, but strongly turbulent due to the magnetorotational instability (MRI). We have carried out large scale magnetohydrodynamic (MHD) simulations to study planet-disk interaction in inviscid but turbulent disks. We revisit the planet gap opening process, and find significant differences between viscous and MRI-turbulent disks. Furthermore, treating the thermal physics more accurately reveals a strong coupling between the planet's gravitational potential and buoyancy waves, which can affect both migration and gap opening. Observationally, recent near-IR spectroscopy, scattered light images, and sub-mm interferometry reveal gaps in protoplanetary disks. These observations, for the first time, put stringent limits on current planet-disk interaction theories. By comparing current theories with observations, we realize another important physics, widely ignored to date, is the dust dynamics in disks. Our recent developments on this problem will also be summarized.