Astron. Astrophys. 327, 273-280 (1997)

Unstable waves in winds of magnetic massive stars

Henning Seemann and Peter L. Biermann

Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany

Received 22 November 1996 / Accepted 2 June 1997

Abstract

We use a luminous fast magnetic rotator model to analyze the influence of a magnetic field on the linear waves induced in the wind of a massive star by the radiative instability. We show that a twisted magnetic field can drive a strong wind with a wind efficiency even without multiple scattering. The radiation amplified waves in the wind are modified by the twisted magnetic field so that they can enhance the wind and lead to overestimates for and . Finally we argue that the spin down time might be consistent with the lifetime derived from the mass loss rate within the uncertainties regarding the stellar structure. Therefore our model may help to explain high, observed values for and without being ruled out by the spin down problem.

Key words: stars: atmospheres stars: magnetic fields stars: mass-loss stars: rotation stars: early-type

Send offprint requests to: seemann@mpifr-bonn.mpg.de

Contents

• 1. Introduction
• 2. The wave equations
• 3. The unperturbed wind models
• 4. Numerical results for waves
  • 4.1. Radial waves
  • 4.2. Nonradial waves
• 5. Consequences from our model
• 6. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: April 8, 1998
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