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.
| Identifer | oai:union.ndltd.org:Potsdam/oai:kobv.de-opus-ubp:1773 |
| Date | January 2007 |
| Creators | de Koter, A., Vink, J. S., Muijres, L. |
| Publisher | Universität Potsdam, Extern. Extern |
| Source Sets | Potsdam University |
| Language | English |
| Detected Language | English |
| Type | InProceedings |
| Format | application/pdf |
| Rights | http://opus.kobv.de/ubp/doku/urheberrecht.php |
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