Slowly Pulsating B and β Cephei are κ mechanism driven pulsating
B stars. That κ 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 logT≈5.3. Theoretical results predict very few SPBs and no
β 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 β Cep
candidates. Though the iron content plays a major role in the excitation of
β 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 β Cep pulsations in early-type stars of the SMC.Comment: 5 pages, 7 figures, to appear under electronic form in : Proceedings
of the 4th HELAS International Conference: Seismological Challenges for
Stellar Structur