Non-adiabatic tidal forcing of a massive, uniformly rotating star -- II. The low-frequency, inertial regime

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Abstract
We study the fully non-adiabatic tidal response of a uniformly rotating unevolved 20-M⊙ star to the dominant l = m = 2 component of the perturbing potential of the companion. This is done numerically with a 2D implicit finite difference scheme. We assume the star is rotating slowly with angular speed ΩS ≪ ΩC, so that the centrifugal force can be neglected, but the Coriolis force is taken fully into account. We study the low-frequency ‘inertial’ regime , where is the forcing frequency in the frame rotating with the stellar spin rate ΩS. In this frequency range inertial modes are excited in the convective core which can interact with rotationally modified g or r modes in the radiative envelope and cause significant strengthening of the tidal interaction. Resonant interaction with quasi-toroidal (r) modes in slightly super-synchronous stars causes efficient spin-down towards corotation. We determine time-scales for tidal spin-up and spin-down in the inertial frequency regime for stars spinning with Ωs = 0.1Ωc and 0.2Ωc.
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