Can mass loss and overshooting prevent the excitation of g-modes in blue supergiants?

被引:44
作者
Godart, M. [1 ]
Noels, A. [1 ]
Dupret, M. -A. [2 ]
Lebreton, Y. [3 ,4 ]
机构
[1] Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium
[2] CNRS, Observ Paris, LESIA, UMR 8109, F-92195 Meudon, France
[3] CNRS, Observ Paris, GEPI, UMR 8111, F-92195 Meudon, France
[4] Univ Rennes 1, IPR, F-35042 Rennes, France
关键词
stars: evolution; stars: mass-loss; stars: oscillations; supergiants; PULSATING B STARS; O-STARS; LOSS RATES; OSCILLATIONS; SAMPLE; METALLICITY; HIPPARCOS; OPACITIES; STELLAR; CODE;
D O I
10.1111/j.1365-2966.2009.14903.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Thanks to their past history on the main-sequence phase, supergiant massive stars develop a convective shell around the helium core. This intermediate convective zone (ICZ) plays an essential role in governing which g-modes are excited. Indeed, a strong radiative damping occurs in the high-density radiative core but the ICZ acts as a barrier preventing the propagation of some g-modes into the core. These g-modes can thus be excited in supergiant stars by the kappa-mechanism in the superficial layers due to the opacity bump of iron, at log T = 5.2. However, massive stars are submitted to various complex phenomena such as rotation, magnetic fields, semiconvection, mass loss, overshooting. Each of these phenomena exerts a significant effect on the evolution and some of them could prevent the onset of the convective zone. We develop a numerical method which allows us to select the reflected, thus the potentially excited, modes only. We study different cases in order to show that mass loss and overshooting, in a large enough amount, reduce the extent of the ICZ and are unfavourable to the excitation of g-modes.
引用
收藏
页码:1833 / 1841
页数:9
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