Long vs short: Quantifying uncertainties in modelling gravity mode period spacing patterns
Abstract
A unique property of gravity mode oscillations is that they form period spacing patterns, where all included oscillations share the same degree and azimuthal order, and are consecutive in radial order. The exact morphology of the patterns depends on the mass, age, rotation, and mixing history of the stars and can therefore be used to probe these exact stellar quantities. The variations in the morphology of the period spacing patterns depend on which radial orders are observed and generally decrease for increasing radial orders. We therefore expect that the asteroseismically determined stellar parameters will have some dependence on not only the number of modes in the pattern (i.e. the pattern length), but also which radial orders are observed. We present the first systematic study of the impact on the asteroseismically derived stellar parameters of Slowly Pulsating B stars arising from varying the length and observed radial orders of their period spacing patterns. These stars have previously been found to have period spacing patterns that include five to 36 gravity mode oscillations. We show that increasing the number of radial orders in the patterns significantly improves the precision on the derived asteroseismic masses, convective core masses, and ages of the stars by a factor of two to four. Furthermore, we show that varying which radial orders are included in a period spacing pattern with fifteen gravity modes causes variations in the estimated masses, convective core masses, and ages of at least 3-5%.