Overstable convective modes of differentially rotating massive main-sequence stars

Overstable convective modes of differentially rotating massive main sequence stars are investigated. We examine the excitation of non-radial oscillations in the envelope by resonance couplings with the overstable convective modes in the rapidly rotating core. It is shown that if differential rotation is assumed such that the convective core rotates more rapidly than the envelope of the star, the overstable convective modes can excite the low-order non-radial g-modes. As the ratio of the angular velocity of the convective core to that of the envelope increases, the order of the non-radial g-modes coupled with the convective mode decreases so that we may observe short-period oscillations excited in an inertial frame. It is also found that when the separation of the frequencies of the consecutive envelope g-modes is wider than the resonance width, there occur strong and weak resonances alternately between the convective modes and the envelope g-modes. (author)