Benchmark Asteroseismic Masses and Ages of Red Giant Stars with TESS

Asteroseismology can provide precise age constraints of stochastically oscillating stars, such as red giants. These masses and ages can be determined through empirical relations which are scaled from the Sun. However, recent studies have shown that the accuracy of these scaling relations can be jeopardized by differences in composition of the stars studied. In particular, metal-poor ([M/H] < -1 dex) star masses can be severely overestimated, and thus the stellar ages can be severely underestimated, when inferred using scaling relations instead of measuring individual mode frequencies and comparing this to stellar models. Here, we present asteroseismic masses and ages using TESS giants light curves of several stars whose kinematics are consistent with different galactic subpopulations that span a range of metallicities, such as the Galactic disk, in situ halo and Gaia-Enceladus populations, from individual frequency modeling. We compare these newly determined masses and ages to those previously determined through global asteroseismic analysis of these stars. We use our revised asteroseismic ages to place new constraints on the age of the Gaia-Enceladus merger event and provide benchmarks for the distribution of stellar ages within different Galactic kinematic substructures. We aim to improve these age estimates and further constrain stellar origins with future spectroscopic followup.