Excitation of g modes in Wolf-Rayet stars by a deep opacity bump
arXiv:astro-ph/0601154 · doi:10.1111/j.1745-3933.2006.00157.x
Abstract
We examine the stability of l=1 and l=2 g modes in a pair of nitrogen-rich Wolf-Rayet stellar models characterized by differing hydrogen abundances. We find that modes with intermediate radial orders are destabilized by a kappa mechanism operating on an opacity bump at an envelope temperature log T ~ 6.25. This `deep opacity bump' is due primarily to L-shell bound-free transitions of iron. Periods of the unstable modes span ~ 11-21 hr in the model containing some hydrogen, and ~ 3-12 hr in the hydrogen-depleted model. Based on the latter finding, we suggest that self-excited g modes may be the source of the 9.8 hr-periodic variation of WR 123 recently reported by Lefevre et al. (2005).
arXiv comment5 pages, 3 figures, accepted by MNRAS letters
References in corpus (5)
- Hydrodynamical Simulations of Corotating Interaction Regions and Discrete Absorption Components in Rotating O-Star Winds
- Synthetic stellar populations: single stellar populations, stellar interior models and primordial proto-galaxies
- Influence of the Coriolis force on the instability of slowly pulsating B stars
- Kappa-mechanism excitation of retrograde mixed modes in rotating B-type stars
- On the excitation of PG1159-type pulsations
Cited by in corpus (10)
- Physical Properties of Wolf-Rayet Stars
- On the role of continuum-driven eruptions in the evolution of very massive stars and Population III stars
- Variability of Young Massive Stars in the Galactic Super Star Cluster Westerlund 1
- Discovery of a variable lead-rich hot subdwarf: UVO 0825+15
- Large-Scale Periodic Variability of the Wind of the Wolf-Rayet Star WR1 (HD 4004)
- Red noise and pulsations in evolved massive stars
- Stable, levitating, optically thin atmospheres of Eddington-luminosity neutron stars
- New Constraints on the Origin of the Short-Term Cyclical Variability of the Wolf-Rayet Star WR 46
- A 10-hour period revealed in optical spectra of the highly variable WN8 Wolf-Rayet star WR 123
- Multiple variability time-scales of the early nitrogen-rich Wolf-Rayet star WR7