Photoevaporation and Disk Dispersal

Abstract

Protoplanetary disks are depleted of their mass on short timescales by viscous accretion, which removes both gas and solids, and by photoevaporation which removes mainly gas. Photoevaporation may facilitate planetesimal formation by lowering the gas/dust mass ratio in disks. Disk dispersal sets constraints on planet formation timescales, and by controlling the availability of gas determines the type of planets that form in the disk. Photoevaporative wind mass loss rates are theoretically estimated to range from ∼ 10-10 to 10-8 M⊙, and disk lifetimes are typically ∼ few Myr.