On multicomponent effects in stellar winds of stars at extremely low metallicity

¹ Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
² Ústav teoretické fyziky a astrofyziky PřF MU, 611 37 Brno, Czech Republic
³ Astronomický ústav, Akademie věd České republiky, 251 65 Ondřejov, Czech Republic
⁴ Bartol Research Institute, University of Delaware, Newark, DE 19716, USA

Corresponding author: J. Krtička, jiri@astro.gla.ac.uk

Received: 29 November 2002
Accepted: 20 February 2003

Abstract

We calculate multicomponent line-driven wind models of stars at extremely low metallicity suitable for massive first generation stars. For most of the models we find that the multicomponent wind nature is not important for either wind dynamics or for wind temperature stratification. However, for stars with the lowest metallicities we find that multicomponent effects influence the wind structure. These effects range from pure heating to possible fallback of the nonabsorbing wind component. We present a simple formula for the calculation of metallicity for which the multicomponent effects become important. We show that the importance of the multicomponent nature of winds of low metallicity stars is characterised not only by the low density of driving ions, but also by lower mass-loss rate.