Bibcode
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
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.