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Andreas Sander, Wolf-Rainer Hamann & Helge Todt

Revised spectral analyses of Galactic WC stars

Article Open Access

Abstract

A grid of models for Wolf-Rayet stars of the carbon sequence (WC) has been established with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. In contrast to earlier versions, clumping and iron line blanketing are now taken into account. The spectra of more than 50 Galactic WC stars with subtypes ranging from WC4 to WC9 have been analyzed by finding the best-fitting model from the grid. While the spectra of Wolf-Rayet stars of the nitrogen sequence (WN) can be nicely reproduced by a PoWR model fit, the WC spectra show a couple of features that cannot be consistently reproduced by a single model. Nevertheless, the models can be applied for their spectral analysis. The obtained parameters clearly reflect the sequence of WC spectral subtypes. From the positions of the WC stars in the Hertzsprung-Russell diagram we conclude that WC stars descend from stars with initial masses between 20 Mo and 40 Mo while stars with higher masses do not reach the WC stage.

Pour citer cet article

Andreas Sander, Wolf-Rainer Hamann & Helge Todt, «Revised spectral analyses of Galactic WC stars», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 80 - Année 2011, 185 - 189 URL : http://popups.ulg.ac.be/0037-9565/index.php?id=2670.

A propos de : Andreas Sander

Institut für Physik und Astronomie, Universität Potsdam, Germany

A propos de : Wolf-Rainer Hamann

Institut für Physik und Astronomie, Universität Potsdam, Germany

A propos de : Helge Todt

Institut für Physik und Astronomie, Universität Potsdam, Germany