Seismology of beta Cephei stars: differentially-rotating models for interpreting the oscillation spectrum of nu-Eridani

TL;DR

This paper presents a novel asteroseismic analysis method for beta Cephei stars using differential rotation models, applied to nu Eridani, revealing insights into internal rotation and mixing processes.

Contribution

It introduces a method analyzing rotational splittings and asymmetries with differentially-rotating models, improving interpretation of oscillation spectra in beta Cephei stars.

Findings

Models with differential rotation fit observed frequencies better.

Predicted asymmetries depend on core overshooting and rotation.

Opposite signs of splitting asymmetries suggest new internal rotation insights.

Abstract

A method for the asteroseismic analysis of beta Cephei stars is presented and applied to the star nu Eridani. The method is based on the analysis of rotational splittings, and their asymmetries using differentially-rotating asteroseismic models. Models with masses around 7.13 M_sun, and ages around 14.9 Myr, were found to fit better 10 of the 14 observed frequencies, which were identified as the fundamental radial mode and the three L=1 triplets g, p, and p. The splittings and aymmetries found for these modes recover those provided in the literature, except for p. For this last mode, all its non-axysimmetric components are predicted by the models. Moreover, opposite signs of the observed and predicted splitting asymmetries are found. If identification is confirmed, this can be a very interesting source of information about the internal rotation profile, in particular in the outer regions of the star. In general, the seismic models which include a description for shellular rotation yield slightly better results as compared with those given by uniformly-rotating models. Furthermore, we show that asymmetries are quite dependent on the overshooting of the convective core, which make the present technique suitable for testing the theories describing the angular momentum redistribution and chemical mixing due to rotationally-induced turbulence.