A grid of 200 000 models of young δ Scuti stars using mesa and GYRE

Abstract

ABSTRACT The rapidly increasing number of delta Scuti stars with regular patterns among their pulsation frequencies necessitates modelling tools to better understand the observations. Further, with a dozen identified modes per star, there is potential to make meaningful inferences on stellar structure using these young δ Sct stars. We compute and describe a grid of >200 000 stellar models from the early pre-main sequence (pre-MS) to roughly one-third of the MS lifetime, and calculate their pulsation frequencies. From these, we also calculate asteroseismic parameters and explore how those parameters change with mass, age, and metal mass fraction. We show that the large frequency separation, Δν, is insensitive to mass at the zero-age main sequence. In the frequency regime observed, the Δν we measure (from modes with n ∼ 5–9) differs from the solar scaling relation by ∼13 per cent. We find that the lowest radial order is often poorly modelled, perhaps indicating that the lower order pressure modes contain further untapped potential for revealing the physics of the stellar interior. We also show that different nuclear reaction networks available in mesa can affect the pulsation frequencies of young δ Sct stars by as much as 5 per cent. We apply the grid to five newly modelled stars, including two pre-MS stars each with 15+ modes identified, and we make the grid available as a community resource.