Convectively-driven internal gravity waves in a massive star

Recent observations of massive stars contain a "red noise" signal which may be an observable manifestation of convectively-driven gravity waves from the stellar core. In this work, we examine the nature of waves driven by core convection and the observable signatures of those waves as they transfer from the radiative-convective interface to the stellar surface. To do so, we study 3D fully compressible spherical simulations of a model of a star, containing a convective core and a stable radiative envelope. We measure both the "pure" wave flux spectrum generated by the convection and the long-term saturated wave signatures at the stellar surface, and compare these results to linear theory. We find good agreement between the linear theory and our fully nonlinear simulations. We speculate about whether the amplitude of waves driven by core convection is large enough to be observable as red noise.