Volume 372, Number 3, June IV 2001
|Page(s)||963 - 980|
|Section||Stellar structure and evolution|
|Published online||15 June 2001|
On the Baldwin effect of He ii emission lines in WR (WN) stars
Astronomical Institute, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
2 SRON Laboratory for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: email@example.com
3 Astronomical Institute "Anton Pannekoek" , University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands e-mail: firstname.lastname@example.org
4 California Institute of Technology, SIRTF Science Center, M/C 100-22, Pasadena CA 91125, USA e-mail: email@example.com
Corresponding author: J. van Gent, firstname.lastname@example.org
Accepted: 6 April 2001
We investigate the relation between the equivalent width of He ii emission lines and the monochromatic continuum luminosity at the line wavelength in the spectra of Wolf-Rayet stars. Model stellar atmospheres and spectra are used to show that the equivalent width inversely correlates with the monochromatic continuum luminosity. We find the effect in Wolf-Rayet star models over a large range of stellar parameters. The effect is shown to be connected to density differences among Wolf-Rayet star winds. The conclusion is drawn that the Baldwin effect may provide a new method for the determination of Wolf-Rayet star distances.
Key words: stars: atmospheres / stars: emission line / stars: Wolf-Rayet
© ESO, 2001
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