Where do Be stars stand in the picture of rotational mixing?
Abstract
Atmospheric parameters and photospheric abundances have been estimated for 60 Be-type stars located in 4 fields over the Magellanic Clouds. Particular attention has been given to the absolute nitrogen abundances to test theories of rotational mixing, an important factor in the evolutionary status of B-type stars, Hunter et al. (2008). The analysis used the non-LTE atmospheric code TLUSTY and required the implementation of a procedure to compensate for possible contamination due to the presence of a circumstellar disc. Through comparison with evolutionary models of fast rotating B-type stars and projected rotational velocity distributions our results support the theory that Be-type stars are typically faster rotators than B stars, but the measured nitrogen enhancements appear to be significantly less than expected for Be stars rotating with velocities greater than 70% of their critical velocity
- Publication:
-
Active OB Stars: Structure, Evolution, Mass Loss, and Critical Limits
- Pub Date:
- July 2011
- DOI:
- 10.1017/S1743921311010027
- Bibcode:
- 2011IAUS..272...85D
- Keywords:
-
- stars: emission-line;
- Be;
- stars: atmospheres;
- stars: rotation;
- stars: evolution;
- stars: abundances;
- (galaxies:) Magellanic Clouds