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arXiv · 1007.3088

Can an underestimation of opacity explain B-type pulsators in the SMC?

S. Salmon·J. Montalbán·A. Miglio·M-A. Dupret·T. Morel·A. Noels
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Abstract

Slowly Pulsating B and $\beta$ Cephei are $\kappa$ mechanism driven pulsating B stars. That $\kappa$ mechanism works since a peak in the opacity due to a high number of atomic transitions from iron-group elements occurs in the area of $\log T \approx 5.3$. Theoretical results predict very few SPBs and no $\beta$ Cep to be encountered in low metallicity environments such as the Small Magellanic Cloud. However recent variability surveys of B stars in the SMC reported the detection of a significant number of SPB and $\beta$ Cep candidates. Though the iron content plays a major role in the excitation of $\beta$ Cep and SPB pulsations, the chemical mixture representative of the SMC B stars such as recently derived does not leave room for a significant increase of the iron abundance in these stars. Whilst abundance of iron-group elements seems reliable, is the opacity in the iron-group elements bump underestimated? We determine how the opacity profile in B-type stars should change to excite SPB and $\beta$ Cep pulsations in early-type stars of the SMC.

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S. Salmon, J. Montalbán, A. Miglio, M-A. Dupret, T. Morel, A. Noels. 2010-07-19. Can an underestimation of opacity explain B-type pulsators in the SMC?. https://arxiv.org/abs/1007.3088

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