EDP Sciences
Free Access
Volume 427, Number 2, November IV 2004
Page(s) 697 - 704
Section Stellar atmospheres
DOI https://doi.org/10.1051/0004-6361:20040506

A&A 427, 697-704 (2004)
DOI: 10.1051/0004-6361:20040506

Grids of model spectra for WN stars, ready for use

W.-R. Hamann and G. Gräfener

Lehrstuhl Astrophysik der Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
    e-mail: wrh@astro.physik.uni-potsdam.de

(Received 24 March 2004 / Accepted 20 July 2004)

Grids of model atmospheres for Wolf-Rayet stars of the nitrogen sequence (WN subclass) are presented. The calculations account for the expansion of the atmosphere, non-LTE, clumping, and line blanketing from iron-group elements. Observed spectra of single Galactic WN stars can in general be reproduced consistently by this generation of models. The parameters of the presented model grids cover the whole relevant range of stellar temperatures and mass-loss rates. We point out that there is a degeneracy of parameters for very thick winds; their spectra tend to depend only on the ratio  $L/{\dot
M}^{4/3}$ . Abundances of the calculated grids are for Galactic WN stars without hydrogen and with 20% hydrogen (by mass), respectively. Model spectra and fluxes are available via internet (http://www.astro.physik.uni-potsdam.de/PoWR.html).

Key words: stars: mass-loss -- stars: Wolf-Rayet -- stars: atmospheres

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