Internal rotation and inclinations of slowly pulsating B stars: Evidence of interior angular momentum transport

Abstract

One of the largest uncertainties in stellar structure and evolution theory is the transport of angular momentum in the stellar interiors. Asteroseismology offers a powerful tool for measuring the internal rotation frequencies of pulsating stars, but the number of such measurements has remained few for $\gtrsim 3\,{\rm M}_\odot$ main-sequence stars. In this work, we compile a list of 52 slowly pulsating B stars for which the interior rotation has been measured asteroseismically. The measurements of the spin parameters, which describe the relative importance of rotation, for the gravito-inertial mode oscillations show that for 40 of the stars the oscillations fall within the sub-inertial regime. We find that the core rotation frequencies of the stars decrease as a function of age, and show evidence of angular momentum transport occurring on the main-sequence. Finally, we derive the inclination angles of the stars, showing that they are generally consistent with the expectations from surface cancellation effects for the given oscillation modes.