Constraints on wind clumping from the empirical mass-loss vs. metallicity relation for early-type stars

  • We present the latest results on the observational dependence of the mass-loss rate in stellar winds of O and early-B stars on the metal content of their atmospheres, and compare these with predictions. Absolute empirical rates for the mass loss of stars brighter than 10$^{5.2} L_{\odot}$, based on H$\alpha$ and ultraviolet (UV) wind lines, are found to be about a factor of two higher than predictions. If this difference is attributed to inhomogeneities in the wind this would imply that luminous O and early-B stars have clumping factors in their H$\alpha$ and UV line forming regime of about a factor of 3--5. The investigated stars cover a metallicity range $Z$ from 0.2 to 1 $Z_{\odot}$. We find a hint towards smaller clumping factors for lower $Z$. The derived clumping factors, however, presuppose that clumping does not impact the predictions of the mass-loss rate. We discuss this assumption and explain how we intend to investigate its validity in more detail.

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Metadaten
Author:A. de Koter, J. S. Vink, L. Muijres
URN:urn:nbn:de:kobv:517-opus-17736
Document Type:Conference Proceeding
Language:English
Date of Publication (online):2008/04/25
Year of Completion:2007
Publishing Institution:Universität Potsdam
Release Date:2008/04/25
RVK - Regensburg Classification:US 1999.07
Organizational units:Extern / Extern
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften
Collections:Universität Potsdam / Tagungen / Clumping in hot-star winds: International Workshop, Potsdam, Germany, 18. - 22. June 2007
Universität Potsdam / Tagungen / Clumping in hot-star winds: International Workshop, Potsdam, Germany, 18. - 22. June 2007 / Talks and Discussions (in alphabetical order)
Universität Potsdam / Tagungen / Clumping in hot-star winds: International Workshop, Potsdam, Germany, 18. - 22. June 2007 / Talks and Discussions (organized by sections) / Spectroscopy and mass loss diagnostic: observations
Licence (German):License LogoKeine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht
Notes extern:
The complete edition of the proceedings "Clumping in hot-star winds" is available:
urn:nbn:de:kobv:517-opus-13981