Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-04-03
Astron.Astrophys. 404 (2003) 975-990
Astronomy and Astrophysics
Astrophysics
17 pages, 20 figures, accepted for publication in A&A
Scientific paper
10.1051/0004-6361:20030512
We examine the properties of Wolf--Rayet (WR) stars predicted by models of rotating stars taking account of the new mass loss rates for O--type stars and WR stars (Vink et al. \cite{Vink00}, \cite{Vink01}; Nugis & Lamers \cite{NuLa00}) and of the wind anisotropies induced by rotation. We find that the rotation velocities $v$ of WR stars are modest, i.e. about 50 km s$^{-1}$, not very dependant on the initial $v$ and masses. For the most massive stars, the evolution of $v$ is very strongly influenced by the values of the mass loss rates; below $\sim$12 M$_\odot$ the evolution of rotation during the MS phase and later phases is dominated by the internal coupling. Massive stars with extreme rotation may skip the LBV phase. Models having a typical $v$ for the O--type stars have WR lifetimes on the average two times longer than for non--rotating models. The increase of the WR lifetimes is mainly due to that of the H--rich eWNL phase. Rotation allows a transition WN/WC phase to be present for initial masses lower than 60 M$_\odot$. The durations of the other WR subphases are less affected by rotation. The mass threshold for forming WR stars is lowered from 37 to 22 M$_\odot$ for typical rotation. The comparisons of the predicted number ratios WR/O, WN/WC and of the number of transition WN/WC stars show very good agreement with models with rotation, while this is not the case for models with the present--day mass loss rates and no rotation. As to the chemical abundances in WR stars, rotation brings only very small changes for WN stars, since they have equilibrium CNO values. However, WC stars with rotation have on average lower C/He and O/He ratios. The luminosity distribution of WC stars is also influenced by rotation.
Maeder Andre
Meynet George
No associations
LandOfFree
Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-730013