Simulation of a Hydrodynamic Stellar Wind from a Rapidly Rotating Star

Abstract

The mechanism for the formation of disk-like flows from rapidly rotating Be stars is not yet clear. An axisymmetric hydrodynamic stellar wind flow from a rapidly rotating star has been simulated numerically as a step in solving this problem. The change in the shape of the star as it rotates and the turbulence excited in the stellar wind at Reynolds numbers ∼10⁹−10¹³ are taken into account. Calculations show the formation of a disk-like flow from the stellar surface at the equator, which expands into the polar regions due to a pressure gradient on scales of the order of the stellar radius. A poloidal velocity vortex is formed at high latitudes. No turbulence is excited near the equator within the simplest standard models and, therefore, no quasi-Keplerian disk-like flow emerges in the equatorial plane. A dependence of the total mass flux on the stellar rotation rate at various surface temperatures has been obtained.