Poster abstract details

The recent identification of candidate \beta Cephei and SPBs in the Magellanic Clouds (MCs) has challenged theoretical instability studies of low metal B stars. Indeed the \kappa mechanism is known to be at the source of self-driven pulsations in main sequence B stars thanks to an opacity bump at T$\ approx$ 200,000 K due to iron group elements. Theoretical computations did not predict excitation of \beta Cephei modes and a few SPB modes at the low values of metallicity encountered in MCs, $Z_{LMC} \approx$0.0046 and $Z_{SMC}\approx 0.0027. In a previous work, we first investigated the effect of adopting a chemical mixture representative of MCs B stars in models. This was not sufficient to explain the presence of B-type pulsators in the MCs. In a continuous effort to solve that enigma, we tested the hypothesis of an underestimation of iron contribution to the stellar opacities. While increases of the opacity greater than 30 \% and 100 \% are needed to obtain excitation of respectively SPB modes and \beta Cephei modes at $Z_{SMC}$, such augmentations are unrealistic in comparison to the estimated uncertainties on iron contribution in calculation of stellar opacities. In this poster, we present the instability analysis of models where we consider now probable underestimations in the opacity due to the other iron group elements, i.e. Ni, Cr and Mn.