Near-core rotation of intermediate-mass stars

Further, we investigate the impact of adding f_rot_ as extra asteroseismic observable aside from the luminosity and effective temperature on the outcome of grid-based modelling from rotating stellar models. We offer a recipe based on linear regression to deduce f_rot_ from the dominant gravito-inertial mode frequency, which we show to be applicable to prograde dipole modes in the sub-inertial regime, having an amplitude above 4mmag.

By applying it to 2497 pulsators with such a mode, we increase the sample of intermediate-mass dwarfs with such an asteroseismic observable by a factor of 4. We use the estimate of f_rot_ to deduce spin parameters between 2 and 6, while the sample's near-core rotation rates range from 0.7% to 25% of the critical Keplerian rate. We use f_rot_, along with the Gaia effective temperature and luminosity to deduce the (convective core) mass, radius, and evolutionary stage from grid modelling based on rotating stellar models.

We derive a decline of f_rot_ with a factor of two during the main-sequence evolution for this population of field stars, which covers a mass range from 1.3M_{sun}_ to 7M_\{sun}. We find observational evidence for an increase in the radial order of excited gravity modes as the stars evolve. For 307 pulsators, we derive an upper limit of the radial differential rotation between the convective core boundary and the surface from Gaia's vbroad measurement and find values up to 5.4.

Our recipe to deduce the near-core rotation frequency from the dominant prograde dipole gravito-inertial mode detected in the independent Gaia and TESS light curves is easy to use and facilitates applications to large samples of pulsators, mapping their angular momentum and evolutionary stage in the Milky Way.