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The Effective Temperatures of Early Wolf-Rayet Stars

Published online by Cambridge University Press:  14 August 2015

Werner Schmutz*
Affiliation:
Institute of Astronomy, ETH-Zentrum, CH-8092 Zurich (Switzerland)

Abstract

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Nussbaumer et al. (1981) (NSSW) have calculated temperatures of 15 Wolf-Rayet stars, which cover most subtypes in the WN and WC sequences. Some Wolf-Rayet stars are found to have a blackbody-like energy distribution and therefore their effective temperature can be well determined, others show deviation from the blackbody shape. This deviation is probably due to an extended continuum emitting region. In view of these later cases NSSW adopted a temperature which they derived from a Zanstra analysis of the He II recombination lines. According to their analysis there should be a continuum jump at 2050 å. New IUE observations of the WN 5 star HD 50896 however did not show any trace of such an absorption edge. This implies that the effective temperature of this WN 5 star and probably of all WR stars with a non blackbody energy distribution is not yet known accurately. Therefore we started a detailed analysis with a spherically symmetric atmosphere model. Though the model has not yet reached its final shape we have obtained as a first result that the location of HD 50896 in the HR-diagram is to the left of the ZAMS and that the Zanstra analysis is indeed not valid for this star.

Type
SESSION 1 — THE WOLF-RAYET PHENOMENON
Copyright
Copyright © Reidel 1982 

References

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