Zhaohuan Zhu (University of Nevada, Las Vegas) - 3-D Views of Planet Formation in Disks: From Inner Magnetospheres to Outer Shadows

Exoplanets form across a wide range of distances from their host stars, from close-in orbits around the central star to the outer protoplanetary disks.  These environments differ dramatically in physical conditions.  In the inner disk, we use 3D magnetohydrodynamical simulations to study magnetospheric accretion and planetary migration in this highly turbulent region.  We find that Earth-mass planets migrate very slowly, often stalling near the dead-zone inner boundary, while giant planets may halt near the magnetospheric truncation radius.  In the outer disk, beyond tens of au, stellar irradiation — especially when modulated by shadows from the inner disk or accretion columns — can drive a variety of disk structures.  Using 3D radiation-hydrodynamical simulations, we show that these shadows act as an asymmetric driving force, leading to spirals and rings.  They can influence planet formation, and their unique velocity features are potentially observable with ALMA molecular line observations.

The Astronomy Colloquium covers a wide range of topics and should be accessible to advanced Astronomy Majors. Refreshments will be served from 3:45 pm with the presentation beginning at 4:00 pm.