Asteroseismology of SPB stars: a comparison of forward asteroseismic modelling results from <i>Kepler</i> and <i>TESS</i>

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 (Transiting Exoplanet Survey Satellite) space telescopes, allows the extraction of their pulsation frequencies and construction of period spacing patterns. Previously, samples of SPB 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, emphasizing the complexities in forward asteroseismic modelling of gravity-mode pulsators with sparsely sampled or short-duration TESS light curves.