Boundary Layers in Pre-Main-Sequence Accretion Disks

Abstract

We present self-consistent solutions, using α-viscosity, for the flow and energetics of optically thick boundary layers in accretion disks around pre-main-sequence stars. The solutions span a range of accretion rates from ˙M=10 -7 to 10 -4 M ○. yr -1 and are in qualitative agreement with observations of T Tauri and FU Orionis stars. The boundary layers in the solutions have two radial zones. The viscous dissipation occurs in a relatively narrow dynamical boundary layer, but most of the energy is actually radiated over a wider thermal boundary layer which extends to larger radii