Modelling OB stars with TESS: Construction of an asteroseismic sample

<p>Lack of high-precision continuous space-photometry has slowed the unlocking of OB star interiors in large numbers from asteroseismology. TESS is now providing data for large samples of stars allowing us to calibrate interior physics such as core overshooting, interior rotation and envelope mixing from pulsation frequencies. Calibrations of this kind are of major importance to quantitatively describe and predict subsequent evolutionary stages and ultimately their stellar remnants. In this talk I will present new results on the largest OB asteroseismic sample with TESS, which focuses on high frequency pulsators. The sample is characterised by a diverse variability, including pulsations, binarity, and rotational modulation connected to spots induced by magnetic fields. As an important test against theory I discuss the placement of the stars in the theoretical pulsation instability strips, computed using the stellar evolution code MESA and the stellar pulsation code GYRE. This test reveals that several stars show pulsational variability not predicted by current models and additional physics needs to be taken into account. This includes rotation, which is especially important as many OB stars are known to rotate at significant fractions of their critical rotation rates and has a profound effect on their pulsation physics. Identifying signatures of rotational modulation in the TESS photometry is therefore of paramount importance as it allows us to measure the surface rotation rate accurately, assess the influence of rotation on the pulsation physics, and remove degeneracies in asteroseismic modelling. The new TESS results of pulsating OB stars allow their pulsational and structural properties to be determined for the first time ever for such a large sample.</p>