The Impact of Accretion Heating and Thermal Conduction on the Dead Zone of Protoplanetary Disks

Abstract

Abstract The paper investigates the influence of accretion heating and turbulent heat conduction on the equilibrium of protoplanetary disks, extending the 2D axisymmetric passive disk model of Flock. The model includes dust sublimation and radiative transfer with the flux-limited diffusion approximation, and predicts the density and temperature profiles as well as the dust-to-gas ratio of the disk. It is shown that the accretion heating can have a large impact: for accretion rates above 5 · 10−8 M ⊙ yr−1 a zone forms behind the silicate condensation front with sufficiently high temperature to sublimate the dust and form a gaseous cavity. Assuming a Prandtl number ∼0.7, it is furthermore shown that the turbulent heat conduction cannot be neglected in the evaluation of the temperature profile. While the inner rim position is not affected by viscous heating, the dead zone edge shifts radially outward for higher accretion rates.