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

Godart, M.; Noels, A.; Dupret, M.-A.; Lebreton, Y.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 396, Issue 4, pp. 1833-1841.

Advertised on:
7
2009
Number of authors
4
IAC number of authors
0
Citations
45
Refereed citations
30
Description
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 κ-mechanism in the superficial layers due to the opacity bump of iron, at logT = 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.
Type