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

arXiv:2607.10834 · astro-ph.SR · Submitted 2026-08-20 · Read on arXiv

Mathijs Vanrespaille, Dario J. Fritzewski, Vincent Vanlaer, Conny Aerts

astro-ph.SR

Submitted: 2026-08-20

Updated: 2026-08-21

Comments: Submitted to Astronomy and Astrophysics

Code: https://github.com/Mathijs-Vanrespaille/Vanrespaille_

License: http://creativecommons.org/licenses/by/4.0/

The gist: Asteroseismic observations of the interior rotation of main sequence stars have shown that angular momentum transport is much more efficient than expected.

Terminology

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. This 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 to maximally exploit their potential to observationally 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, 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 main sequence 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. The rotation rate in at least 14 stars varies by more than 10%. Of these 14 stars, ten have their rotation rate decreasing from the core to the surface while it is the opposite in four of them. We affirm that radial differential rotation is common in beta Cep stars. Moreover, our constrained rotation profiles suggest that the typical beta Cep rotation profile may be non-monotonic.

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