Abstract
Stellar structure models which were generated to match the photometric and binary properties of the B1.5 IV star Spica (Alpha Vir) are analyzed for pulsation characteristics. The pulsation computations were linear and adiabatic and included both radial and nonradial (l = 2) motions. Three sets of models were tested: normal evolution using Cox-Stewart opacities, normal evolution using opacities increased substantially over Cox-Stewart, and evolution models using Cox-Stewart opacities but with a nonshrinking convective core. The models which most closely agree with the photometric, orbital, and Beta Cephei pulsation characteristics are those with opacities increased over Cox-Stewart, and which are either at the end of overall contraction or at the initial hydrogen shell ignition. The most likely mode of pulsation is nonradial gl mode which contains two extra nodes in the radial eigenfunction, although the radial first-harmonic might also be a candidate.