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Theories for the Winds from Wolf Rayet Stars

Published online by Cambridge University Press:  14 August 2015

Joseph P. Cassinelli*
Affiliation:
University of Wisconsin-Madison

Abstract

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The massive and fast winds of Wolf Rayet stars present a serious momentum problem for the line-driven wind theories that are commonly used to explain the fast winds of early type stars. It is perhaps possible for the winds to be driven by lines, if multiple scattering occurs and if there are a sufficient number of lines in the spectrum so that large fraction of the continuum is blocked by line opacity in the winds. Several other mechanisms are discussed, in particular two that rely on strong magnetic fields: a) Alfven wave driven wind models like those recently developed by Hartmann and MacGregor for late type supergiants and b) the “Fast Magnetic Rotator” model that was developed by Belcher and MacGregor for the winds from pre-main sequence stars. In either model, large magnetic fields (≈104 gauss) are required to drive the massive and fast winds of Wolf Rayet stars. Smaller fields might be possible if the multiple scattering line radiation force can be relied on to provide a final acceleration to terminal velocity.

Type
SESSION 3 — MASS-LOSS FROM WR STARS: OBSERVATIONS AND THEORY
Copyright
Copyright © Reidel 1982 

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