A systematic study of stellar models for C/O-rich Wolf-Rayet Stars

Extract

A grid of homogeneous stellar models for Wolf-Rayet stars in the mass range from 1 to 60 M_⊙ has been computed. For each stellar mass, stars with eight different sets of chemical compositions — from pure helium stars with (Y,C,O)=(1,0,0) to extreme helium poor stars with (Y,C,O)=(0.02,0.11,0.87) — have been calculated in order to investigate the dependence of the stellar structure on the stellar mass and chemical composition. Modern input physics adapted to the exotic chemical composition of the Wolf-Rayet stars has been incorporated in the models, including effects of partial recombination of helium, carbon, and oxygen, and detailed opacity tables for 20 different combinations of the (Y,C,O)-abundances. Furthermore, we estimated the effect of the intense, partly optically thick Wolf-Rayet winds on their apparent effective temperature, using the formalism of de Loore et al. (1982, IAU-Symp. 99, 53) with the parameters: = 3 . 10⁻⁵M_⊙yr⁻¹, β = 2, and v_∞ = 2000 km s⁻¹.