Query : 2005A&A...429..581M

2005A&A...429..581M - Astronomy and Astrophysics, volume 429, 581-598 (2005/1-2)

Stellar evolution with rotation. XI. Wolf-Rayet star populations at different metallicities.


Abstract (from CDS):

Grids of models of massive stars (M≥20M) with rotation are computed for metallicities Z ranging from that of the Small Magellanic Cloud (SMC) to that of the Galactic Centre. The hydrostatic effects of rotation, the rotational mixing and the enhancements of the mass loss rates by rotation are included. The evolution of the surface rotational velocities of the most massive O-stars mainly depends on the mass loss rates and thus on the initial Z value. The minimum initial mass for a star for entering the Wolf-Rayet (WR) phase is lowered by rotation. For all metallicities, rotating stars enter the WR phase at an earlier stage of evolution and the WR lifetimes are increased, mainly as a result of the increased duration of the eWNL phase. Models of WR stars predict in general rather low rotation velocities (<50km/s) with a few possible exceptions, particularly at metallicities lower than solar where WR star models have in general faster rotation and more chance to reach the break-up limit. The properties of the WR populations as predicted by the rotating models are in general in much better agreement with the observations in nearby galaxies. Some possible remaining difficulties in these comparisons are mentioned. The evolution of the chemical abundances is largely influenced by rotation in all phases from the MS phase to the WN and WC phases. We also show that the interval of initial masses going through the LBV stage is changing with Z and Ω. The observed variation with metallicity of the fractions of type Ib/Ic supernovae with respect to type II supernovae as found by Prantzos & Boissier (2003A&A...406..259P) is very well reproduced by the rotating models, while non-rotating models predict much too low ratios. This indicates that the minimum initial masses of single stars going through a WR phase are consistently predicted. At Z=0.040, stars with initial masses above 50M reach a final mass at the time of supernova explosion between 5 and 7.5M, while at Z=0.004, like in the SMC, the final masses of stars are in the range of 17-29M. On the whole, rotation appears to be an essential parameter even for the WR properties. Detailed tables describing the evolutionary tracks are available on the web.

Abstract Copyright:

Journal keyword(s): stars: evolution - stars: rotation - stars: Wolf-Rayet

Simbad objects: 8

goto Full paper

goto View the references in ADS

Number of rows : 8
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 IC 10 G 00 20 25.50 +59 17 17.0   13.6 9.5     ~ 1106 1
2 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12475 1
3 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 10929 1
4 NGC 300 GiG 00 54 53.4465638304 -37 41 03.168402396 8.83 8.69 8.13 7.46   ~ 1471 2
5 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 5764 1
6 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6897 1
7 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17110 1
8 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14051 0

To bookmark this query, right click on this link: simbad:objects in 2005A&A...429..581M and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact