Viscous decretion discs around rapidly rotating stars

We discuss steady viscous Keplerian decretion discs around rapidly rotating stars. We assume that low-frequency modes, which may be excited by the opacity bump mechanism, convective motion in the core, or tidal force if the star is in a binary system, can transport a sufficient amount of angular momentum to the region close to the stellar surface. Under this assumption, we construct a star-disc system, in which there forms a viscous decretion disc around a rapidly rotating star because of the angular-momentum supply. We find a series of solutions of steady viscous decretion discs around a rapidly rotating star that extend to R_disc ≳ 10R*, with R* being the equatorial radius of the star, depending on the amount of angular momentum supply.