MAGNETOHYDRODYNAMIC STELLAR WINDS - A NEW CLASS OF SOLUTIONS

This paper introduces a new class of analytic MHD solutions for steady , axisymmetric, rotating outflows interacting with poleward deflected, partially open magnetic fields. In the first paper of this series, se veral simplifying assumptions were necessary to deal with the problem in an analytical fashion, One of the most important restrictive hypoth eses is the spherical symmetry of the Mach-Alfven surfaces. This condi tion is relaxed in this work, and general colatitude-dependent Alfveni c surfaces are assumed. As an example of the method, approximate solut ions are found for a purely radial magnetic configuration and for init ially superalfvenic outflows, by assuming a small-amplitude anisotropi c component of the Mach-Alfven function regarding the spherically symm etric part. It is shown that the general behavior of the stellar wind drastically changes. Particularly, for the sample of solutions derived here it is found that the terminal velocity of the wind does not dive rge and increases with rotation. The energy distribution needed to sus tain the outflow consists of a heating source located close to the pho tosphere, and its rate is much smaller than the blackbody power radiat ed by the star. The temperature profile displays the typical chromosph eric structure of early-type stars once its associated set of boundary conditions is given.