Asteroseismology of SPB stars: a comparison of forward asteroseismic modelling results from Kepler and TESS

TL;DR

This study compares asteroseismic modeling results of SPB stars from Kepler's long-duration data and TESS's shorter, intermittent observations, highlighting both agreements and challenges in deriving stellar parameters.

Contribution

It demonstrates the potential and limitations of using TESS data for asteroseismic modeling of SPB stars compared to Kepler data.

Findings

Some TESS-based results agree with Kepler-derived parameters.

Shorter TESS data can lead to incompatible modeling results.

Complexities arise in modeling gravity-mode pulsators with sparse data.

Abstract

The slowly pulsating B (SPB) stars are a class of variable star with masses between about 3 and 8 M$_{\odot}$. Their gravity-mode pulsation frequencies are sensitive to the near-core structure, which makes them useful probes of rotation and mixing in the deep stellar interior. Time series photometry, such as from the Kepler and TESS space telescopes, allows the extraction of their pulsation frequencies and construction of period spacing patterns. Previously, samples of slowly pulsating B stars were observed by the Kepler mission and underwent forward asteroseismic modelling to retrieve stellar parameters such as mass, age and core mass. However, all of these stars have since been re-observed by the ongoing TESS mission with light curves that are usually shorter and non-continuous, resulting in more difficult frequency extraction and interpretation in terms of constructing period spacing patterns. In this paper we compare the results of forward asteroseismic modelling of a sample of SPB stars using intermittent TESS light curve data to those based on long-duration Kepler light curves. We show how in some cases that the masses and core masses derived from only a few sectors of TESS data agree well with the 4-yr Kepler mission results, despite the stars having far fewer significant pulsation frequencies in their TESS light curves. However, some stars yield incompatible results, emphasising the complexities in forward asteroseismic modelling of gravity-mode pulsators with sparsely sampled or short duration TESS light curves.