The Prospects for Hurricane-like Vortices in Protoplanetary Disks

Abstract

When ice on the surface of dust grains in protoplanetary disk sublimates, it adds its latent heat of water sublimation to the surrounding flow. Drawing on the analogy provided by tropical cyclones on Earth, we investigate whether this energy source is sufficient to sustain or magnify anticyclonic disk vortices that would otherwise fall victim to viscous dissipation. An analytical treatment, supported by exploratory two-dimensional simulations, suggests that even modestly undersaturated flows can extend the lifetime of vortices, potentially to a degree sufficient to aid particle trapping and planetesimal formation. We expect the best conditions for this mechanism to occur will be found near the disk’s water ice line if turbulent motions displace gas parcels out of thermodynamic equilibrium with the dust midplane.