- Observational constraints on mass loss and evolution of massive stars
- Astronomical Society of the Pacific conference series
- Pages (from-to)
- Document type
- Faculty of Science (FNWI)
- Anton Pannekoek Institute for Astronomy (API)
We review the empirical mass-loss properties of early-type stars in the upper part of the Hertzsprung-Russell diagram. Specifically, we focus on the relation between mass loss and chemical composition by comparing properties of massive stars in our galaxy with those in the Magellanic Clouds. The first robust empirical calibration of this relation is discussed, yielding dM/dt Z0.83±0.16, where Z is the metallicity. This compares well with theoretical expectations. It is pointed out that the largest uncertainties in the power-law index of this relation are likely connected to uncertainties in abundances, in particular of objects in the Small Magellanic Cloud. The role of clumping in stellar winds is discussed. Using Hα as the prime diagnostic, a comparison of the empirical and predicted dM/dt (Z) suggests that the outflows are only modestly clumped, with clumping factors in the Hα line forming region of about 3-5. If the properties of clumping are independent of chemical environment, the dM/dt (Z) power-law index is not affected by the actual value of the clumping factor.
- Proceedings title: Mass loss from stars and the evolution of stellar clusters: Proceedings of a workshop held at Lunteren,
the Netherlands, 29 May-1 June 2006
Publisher: Astronomical Society of the Pacific (ASP)
Place of publication: San Francisco, CA
Editors: A. de Koter, L.J. Smith, L.B.F.M. Waters
If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.