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arXiv · 2607.10834

Asteroseismic forward modelling of 36 $\beta$ Cep pulsators and inferences on their internal differential rotation

Mathijs Vanrespaille·Dario J. Fritzewski·Vincent Vanlaer·Conny Aerts
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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. Differential rotation has been detected in several massive main sequence $\beta$ Cep pulsators, even though fewer than ten $\beta$ Cep stars have been asteroseismically modelled in detail so far. 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 constrain their rotation profiles. We searched for rotational splitting 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 the rotation rate decreases with radius while it increases in three other stars, and two display non-monotonic rotation profiles. We affirm that radial differential rotation is common in $\beta$ Cep stars. Moreover, our constrained rotation profiles suggest that $\beta$ Cep rotation profiles may be non-monotonic.

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Mathijs Vanrespaille, Dario J. Fritzewski, Vincent Vanlaer, Conny Aerts. 2026-07-12. Asteroseismic forward modelling of 36 $\beta$ Cep pulsators and inferences on their internal differential rotation. https://arxiv.org/abs/2607.10834

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