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Stothers, R., 1976: Theoretical models of Beta Cephei stars constructed with new radiative opacities. Astrophys. J., 210, 434-439.
Theoretical models of stars in the mass range of β Cephei stars have been computed with Carson's new radiative opacities from the zero-age main sequence up to the stage of core helium ignition. The new models lying off the zero-age main sequence possess cooler effective temperatures than do models based on earlier opacities, and cross the observed β Cephei strip in the H-R diagram only once. This intersection occurs during the main phase of core hydrogen burning. Nonadiabatic pulsational properties of the models during this phase of evolution have been derived in the linear approximation. The pulsation constants and period ratios for both radial (I = 0) and nonradial (I = 2) modes turn out to be systematically (though not largely) different from those possessed by models based on earlier opacities. Cases of two modes with close periods are pointed out that may possibly account for the "beat" phenomenon observed in many β Cephei stars. The observed phase lag of 90° between the light and radial-velocity curves is predicted correctly along the intersection strip for many of the modes. But all the modes that have been tested for actual instability, viz., those with 0 ≤ I ≤ 5 and 0.02 ≤ Q(day) ≤ 0.06, turn out to be stable.
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