Winds from fast rotating stars

Abstract

ABSTRACT Numerical modelling of an isothermal wind from a fast rotating star is performed. Excitation of hydrodynamical turbulence and deviation of the shape of the stellar surface from a sphere are taken into account. Rotation and turbulence result in a dramatic increase of the mass flow rate from the star in comparison with a non-rotating one. The outflow occurs predominantly from a region on the stellar surface located at the equator. This flow expands rapidly due to thermal pressure. However, a disc-like flow at the equator is formed. The flow is more complicated near the pole. At large distances from the star a radially expanding wind is formed while close to the star some fraction of the outflow from the equatorial region falls down on to the stellar surface, producing a huge vortex. The dependence of the mass loss rate on the parameters of the star is presented.