Oral Presentation

Dust settling in turbulent protoplanetary disks

Author(s): Min-Kai Lin (ASIAA)

Presenter: Min-Kai Lin (ASIAA)

Planets are built from planetesimals, themselves built from small dust grains in gaseous protoplanetary disks. Planetesimal formation mechanisms often invoke collective effects of dust grains. However, these processes are only active if the disk's local dust-to-gas ratio is significantly enhanced beyond the typical interstellar medium value of one per cent. One way to achieve this is dust settling towards the disk mid-plane. On the other hand, turbulence within the disk would oppose dust sedimentation. I present numerical simulations of dusty-gas in protoplanetary disks with focus on dust settling against hydrodynamic turbulence generated by the `vertical shear instability' (VSI). The VSI tends to lift particles, which would be problematic for planetesimal formation. I explore regions of parameter space where dust settling can nevertheless occur. Specifically, I focus on the effect of dust-on-gas drag forces in stabilizing the VSI, thereby allowing dust settling and favoring planetesimal formation.