Planet Embryos in Vortex Wombs Available to Purchase

One of the enduring puzzles in the formation of planetary systems is how millimeter‐sized dust grains agglomerate to become kilometer‐sized, self gravitating planetesimals, the “building blocks” of planets. One theory is that the dust grains settle into the mid‐plane of the protoplanetary disk (thin, cool disk of gas and dust in orbit around a newly forming protostar) until they reach a critical density that triggers a gravitational instability to clumping. However, turbulence within the disk is likely to stir up the dust grains and prevent them from reaching this critical density. A competing theory is that dust grains grow by pair‐wise collisions, forming fractal structures. It is unclear, however, how robust such structures would be to successive collisions. A new and exciting theory is that vortices in a protoplanetary disk may capture dust grains at their centers, “seeding” the formation of planetesimals. We are investigating the dynamics of 3D vortices in protoplanetary disks with a parallel spectral code on the Blue Horizon supercomputer. Some of the lingering questions we address are: What is the structure of 3D vortices in a protoplanetary disk? Are they columns that extend vertically through the disk, through many scale heights of pressure and density? Or are they more “pancake‐like” and confined to the mid‐plane? Are the vortices stable to small perturbations, such as vertical shear? Are 3D vortices robust and long‐lived coherent structures? Do small vortices merge to form larger vortices the way vortices on Jupiter do?