A grid of 200,000 models of young $\delta$ Scuti stars using MESA and GYRE

TL;DR

This paper presents a comprehensive grid of over 200,000 stellar models of young delta Scuti stars, analyzing their pulsation frequencies to improve understanding of stellar structure and evolution.

Contribution

The study provides a large, detailed model grid of young delta Scuti stars, including pulsation calculations and analysis of how parameters affect frequencies, with application to observed stars and community sharing.

Findings

Large frequency separation is insensitive to mass at zero-age main sequence.

Measured large frequency separation differs from solar scaling by ~13%.

Nuclear reaction networks can alter pulsation frequencies by up to 5%.

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 $\delta$ Sct stars. We compute and describe a grid of $>$200,000 stellar models from the early pre-main-sequence to roughly one-third of the main-sequence 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, $\Delta\nu$, is insensitive to mass at the zero-age main sequence. In the frequency regime observed, the $\Delta\nu$ we measure (from modes with $n\sim5$--9) differs from the solar scaling relation by $\sim$13%. 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 $\delta$ Sct stars by as much as 5%. We apply the grid to five newly modelled stars, including two pre-main-sequence stars each with 15+ modes identified, and we make the grid available as a community resource.