Magnetically confined winds of hot stars

Abstract

We discuss the interplay between radiatively driven winds andmagneticfields in hot stars.In late main sequence B stars, radiatively driven winds are likelytooccur but with a mass loss ratestrongly affected by the magnetic field structure at the stellarsurface.Away from the stellar surface, the interaction of a radiativelydrivenwind with a dipolar magnetic field leadto the formation of a large magnetosphere consisting of anextended hotpostshock region as well as a dense coolingdisk forming near the magnetic equator (Magnetically Confined WindShockModel, MCWS).In the context of this model, we try to interpret an extensive setof observations (X-ray, UV and optical data) available for the O7VstarΘ¹ Ori C as wellas the pulsating B star β Cep. We finallyshow how observations of X-ray lines with the XMM or Chandraspacecraftscould help us to obtain a clearer pictureof the interaction between magnetic fields and the winds of hotstars.