SIMBAD references

2011MNRAS.412.1814S - Mon. Not. R. Astron. Soc., 412, 1814-1822 (2011/April-2)

Linear analyses for the stability of radial and non-radial oscillations of massive stars.


Abstract (from CDS):

In order to understand the periodic and semiperiodic variations of luminous OBA-type stars, linear non-adiabatic stability analyses for radial and non-radial oscillations have been performed for massive evolutionary models (8-90 M). In addition to radial and non-radial oscillations excited by the kappa-mechanism and strange mode instability, we discuss the importance of low-degree oscillatory convection (non-adiabatic g) modes. Although their kinetic energy is largely confined to the convection zone generated by the Fe-opacity peak near 2 {x} 105 K, the amplitude can emerge into the photosphere and should be observable in a certain effective temperature range. They have periods longer than those of the radial strange modes so that they seem to be responsible for some of the long-period microvariations of Luminous Blue Variables (LBVs; S Dor variables) and α Cyg variables. Moreover, monotonically unstable radial modes are found in some models whose initial masses are greater than or equal to 60 M with Z= 0.02. The monotonic instability probably corresponds to the presence of an optically thick wind. The instability boundary roughly coincides with the Humphreys-Davidson limit.

Abstract Copyright: 2011 The Author Monthly Notices of the Royal Astronomical Society2011 RAS

Journal keyword(s): stars: early-type - stars: evolution - stars: massive - stars: oscillations - supergiants

Simbad objects: 7

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