Photoevaporated disks around massive young stars

Abstract

We present a parametric model of an isothermal photoevaporating wind from a Keplerian disk around a young massive star. The wind is produced by high-energy photons (h >13:6 eV) from the massive central star that ionize and heat the material of the circumstellar disk, as discussed several years ago by Hollenbach and coworkers. The model gives the velocity and density structure of the ionized winds. Because of its simplicity, it is very useful to explore the physical conditions of this type of wind. The model can also describe the photoevaporation of disks around low-mass young stars. We obtain the free-free continuum emission of the photoevaporated flows and compare with the spectral energy distribution of the known bipolar sources MWC 349 A and NGC 7538 IRS 1.