Motions of Dusty Clumps in the Protoplanetary Disk MWC 758?

ABSTRACT :
Dusty clumps in protoplanetary disks have been widely postulated to be vortices. They are important for concentration and growth of dust grains in the planet formation process, and can also point to possible planetary perturbers in the disks. Their dynamics has been challenging to study because the dust continuum emission does not have kinematical information. To reveal their dynamics, we used the high-resolution continuum images of the protoplanetary disk of MWC 758 obtained with ALMA across a 4-year baseline, and measured the time variations of their locations and intensity distributions. We found that their proper motions do not follow Keplerian rotation, inconsistent with conventional vortex theory. Their deviations from local Keplerian motion are likely due to their interaction with the spirals and eccentric ring in the disk, as also seen in the variations of their intensity distribution. In this presentation, I will introduce our results of the time variations of the dust clumps and discuss their implications in the context of vortex dynamics and disk morphology.