Domains of pulsational instability of low-frequency modes in rotating upper main sequence stars

Abstract

We determine instability domains on the Hertzsprung–Russell diagram for rotating main sequence stars with masses of 2–20 M⊙. The effects of the Coriolis force are treated wihin the traditional approximation. High-order g modes with harmonic degrees ℓ up to 4 and mixed gravity–Rossby modes with |m| up to 4 are considered. We include the effects of rotation in wider instability strips for a given ℓ compared to the non-rotating case and in an extension of the pulsational instability to hotter and more massive models. We present results for a fixed value of the initial rotation velocity as well as for a fixed ratio of the angular rotation frequency to its critical value. Moreover, we check how the initial hydrogen abundance, metallicity, overshooting from the convective core and opacity affect the pulsational instability domains. The effect of rotation on the period spacing is also discussed.