Radiation Hydrodynamics Simulations of Protoplanetary Disks: Stellar Mass Dependence of the Disk Photoevaporation Rate

Abstract

Abstract Recent multiwavelength observations suggest that inner parts of protoplanetary disks (PPDs) have shorter lifetimes for heavier host stars. Since PPDs around high-mass stars are irradiated by strong ultraviolet radiation, photoevaporation may provide an explanation for the observed trend. We perform radiation hydrodynamics simulations of photoevaporation of PPDs for a wide range of host star mass of M * = 0.5–7.0 M ⊙. We derive disk mass-loss rate M ̇ , which has strong stellar dependence as M ̇ ≈ 7.30 × 10 − 9 ( M * / M ⊙ ) 2 M ⊙ yr − 1 . The absolute value of M ̇ scales with the adopted far-ultraviolet and X-ray luminosities. We derive the surface mass-loss rates and provide polynomial function fits to them. We also develop a semianalytic model that well reproduces the derived mass-loss rates. The estimated inner-disk lifetime decreases as the host star mass increases, in agreement with the observational trend. We thus argue that photoevaporation is a major physical mechanism for PPD dispersal for a wide range of the stellar mass and can account for the observed stellar mass dependence of the inner-disk lifetime.