Stellar Astrophysics and Galactic Archaeology with Asteroseismology
Christopher Lindsay, Yale University
The analysis of stellar oscillations has enabled detailed asteroseismic studies of the internal structures of stars, particularly subgiants and red giants. Because many areas of astrophysics depend on accurate stellar modeling, asteroseismology provides a vital tool for improving our understanding of how astrophysical systems evolve over time. In this talk, I will describe my research using data from the Kepler and TESS missions to model stars in detail using their individual oscillation frequencies, thereby probing their interiors. I will discuss how detailed asteroseismic modeling enables precise age determinations for notable stars. As an example, I will present the asteroseismic modeling of a sample of evolved metal-poor, α-enhanced stars in the Milky Way’s stellar halo, comparing a full treatment of α-enhancement against ad hoc metallicity corrections. We find that both approaches yield consistent stellar parameters with comparable uncertainties when individual oscillation mode frequencies are used for stellar modeling, in turn also indicating a breakdown of widely used asteroseismic scaling relations in this regime. I will also show how asteroseismic measurements can inform the treatment of convective boundaries in stellar models, particularly for red giants and stars with convective cores.