A rotating, magnetic, radiation-driven wind model for Wolf-Rayet stars

Abstract

A radiation-driven wind model that incorporates the effects of rotation and an open magnetic field is applied to WR stars in order to address the wind momentum problem. The dependence of the mass-loss rate and terminal velocity on the rotation rate and surface magnetic field is studied for the flow in the equatorial region. The transition from a purely radiatively driven wind to a rotationally and magnetically driven wind is investigated for the case in which the stellar luminosity is consistent with Maeder's mass-luminosity relation. An alternative picture for WR winds is developed in which there is a slower but denser equatorial flow and a fast radiation-driven wind at higher latitudes. Wind models for several stars are presented that are consistent with interior theory. If the stars have field of about 1500 G and rotate at rates greater than about 85 percent maximum, they can satisfy the radio and UV observations and explain the momentum problem, and also overcome the spindown problem. 52 references.