Rotation and magnetic fields during the evolution of massive stars through B(e) and Wolf-Rayet phases

The wind phenomena of a variety of early-type stars, including the evolved B(e) and Wolf-Rayet (W-R) stars, have been explained using the presence of rotation and magnetic fields. However, if a star had a significant wind throughout its previous evolutionary lifetime, spin-down would have occurred. This paper is a first step in an exploration of possible evolutionary scenarios of rotation in massive stars with continuous winds, from zero-age main sequence (ZAMS) through terminal W-R stage. Magnetic fields with varying strengths are considered. A kinematic approach is developed to derive equations for the evolution of angular momentum. The equations are applied to heuristic models that represent single stars with a ZAMS mass of 60 solar mass. Computations are performed for models with different internal angular velocity distributions. Omnidirectional and two-component winds are considered, and, in some models, allowance is made for possible bipolar mass ejection at the Humphreys-Davidson (HD) limit. The effects of the important factors that govern the evolution of the equatorial rotation are discussed.