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

Abstract

We study the fully non-adiabatic tidal response of a uniformly rotating unevolved 20 Msun star to the dominant l=m=2 component of the companion's perturbing potential. This is done numerically with a 2D implicit finite difference scheme. We assume the star is rotating slowly, 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 the tidal oscillation frequency in the frame corotating with the star is less than twice the stellar spin rate. 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.