Anuj Gautam

Quantifying Systematic Uncertainties in δ Sct Star Modelling for Asteroseismic Age-dating

Determining accurate stellar ages has implications for various areas of astrophysics, from understanding our Galaxy’s chemical evolution to refining models of protoplanetary disc formation and evolution. However, stellar ages cannot be directly measured and must instead be estimated or inferred. Asteroseismology—the study of stellar pulsations—is one of the most promising methods for inferring stellar ages, but its accuracy depends heavily on the theoretical stellar models used, which suffer from poorly characterised uncertainties. We have quantified systematic age uncertainties for 1.5-2.5 Msun delta Scuti stars. To support this, we present a comprehensive grid of 60 million stellar pulsation models, computed using the MESA and GYRE codes. In contrast to previous work, such as Murphy et al. (2023), our models incorporate four key advancements: uniform rotation; an extended age range; an extension of mode degrees up to ell=3; and the inclusion of g-modes, mixed modes, and their avoided crossings. We examine the effects of key physical parameters, such as convective overshoot, mixing length alpha, and nuclear reaction networks, on the stellar pulsation frequencies. This grid and the associated systematic uncertainty study will be made available to the community. Its first application will be to refine the age of the Pleiades.