Asteroseismic forward modelling of 36 $β$ Cep pulsators and inferences on their internal differential rotation
Year: 2026
Type: preprint
Abstract: Asteroseismic observations of the interior rotation of main sequence stars have shown that angular momentum transport is much more efficient than expected. Which transport mechanisms are responsible for this is still unclear. Detections of radial differential rotation provide valuable constraints on these transport mechanisms. We aim to expand the sample of asteroseismically forward modelled \{beta} Cep pulsators and exploit their potential to constrain angular momentum transport mechanisms. To that end, we seek to place constraints on their rotation profiles. We searched for the rotational splittings of non-radial modes in a large \{beta} Cep sample with identified mode degrees. These were subjected to a novel forward modelling approach involving a 6-dimensional parameter space, which consistently accounts for second-order rotation effects using the state-of-the-art StORM oscillation code. We successfully modelled 36 \{beta} Cep stars and constrained crucial parameters such as their initial mass, internal rotation frequency, convective core mass, and age. Like in intermediate-mass stars, the internal rotation rate globally decreases in \{beta} Cep stars as they evolve along the main sequence. Radial differential rotation is constrained in 17 \{beta} Cep stars. We detect statistically significant deviations from quasi-rigid rotation in 13 stars. Our constraints on eight of these 13 stars indicate that the rotation rate decreases with radius between the layers probed by the identified modes while it increases in three other stars. Two stars with rotation constraints at three or more points display non-monotonic rotation profiles. We affirm that radial differential rotation is common in \{beta} Cep stars. Moreover, our constraints on the internal rotation are compatible with non-monotonic rotation profiles obtained from hydrodynamical simulations and rotation inversions.
Source: arXiv (Cornell University)
Institution: KU Leuven
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7168265039