Vortex Formation and Survival in Protoplanetary Disks subject to Vertical Shear Instability
Several protoplanetary disks observed by ALMA show dust concentrations consistent with particle trapping in giant vortices. The formation and survival of vortices is of major importance for planet formation, because vortices act as particle traps and are therefore preferred locations of planetesimal formation.
Recently, Richard et. al. showed that the vertical shear instability (VSI) is capable of generating turbulence in protoplanetary disks that have the proper radial and vertical stratification and thermally relax on sufficiently short time scales. However, these studies found only small vortices, which are also short-lived in nature. But these studies were performed simulating only a small azimuthal range of the disk.
We present 3D hydrodynamic simulations investigating the effect of the azimuthal extent of the simulation on vortex formation and lifetime. We show that vortices do form and can exist at least several hundred orbits in simulations covering a disk with 180 deg or more in azimuth, suggesting the VSI to be capable to form vortices or at least to trigger vortex formation via a secondary instability, e.g. Rossby Wave Instability. Vortices once formed are sustained for at least hundreds of local orbits.
Richard S., Nelson R. P., Umurhan O. M., 2016, MNRAS,456, 3571
Manger N., Klahr H., 2018, MNRAS, subm.