The nature of the Wolf-Rayet phenomenon: mass loss close to the Eddington limit
Götz Gräfener and Wolf-Rainer Hamann
With the new Potsdam Wolf-Rayet (PoWR) hydrodynamic atmosphere models we have obtained the first fully self-consistent wind models for WR stars. We find that WR-type mass loss is initiated when stars approach the Eddington limit. For the most massive stars this happens already at the end of their main-sequence lifetime, i.e. still in the H-burning phase. Less massive objects enter the Wolf-Rayet stage after the onset of He-burning. From spectral analyses with hydrodynamic models we estimate the masses of two extremely luminous, H-rich WNL stars in Carina OB 1. With present masses of at least 80-100 M_sun, these stars are the direct descendants of the most massive stars in the galaxy.
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