Radial and nonradial oscillations of massive supergiants
arXiv:1010.2583 · doi:10.1017/S1743921311011112
Abstract
Stability of radial and nonradial oscillations of massive supergiants is discussed. The kappa-mechanism and strange-mode instability exciteoscillations having various periods in wide ranges of the upper part of the HR diagram. In addition, in very luminous () models, monotonously unstable modes exist, which probably indicates the occurrence of optically thick winds. The instability boundary is not far from the Humphreys-Davidson limit. Furthermore, it is found that there exist low-degree() oscillatory convection modes associated with the Fe-opacity peak convection zone, and they can emerge to the stellar surface so that they are very likely observable in a considerable range in the HR diagram. The convection modes have periods similar to g-modes, and their growth-times are comparable to the periods. Theoretical predictions are compared with some of the supergiant variables.
arXiv comment7 pages, 5 figures, IAU symposium No.272, 2010 "Active OB stars: structure, evolution, mass loss, and critical limits" Eds. C. Neiner, G. Wade, G. Maynet, & G. Peter