Grid-based modelling of low-metallicity red giants utilising individual asteroseismic frequencies

We present the modelling of the low-metallicity Kepler red giants KIC 4671239 (Hennes) and KIC 7693833 (Rogue), which have been persistently challenging to characterise in accordance with expectations. We employ a grid-based modelling approach, where the observed stellar parameters are fitted to a grid of stellar models using the BAyesian STellar Algorithm (BASTA). Applying this to singular stars entails creating highly specialised grids suitable for the individual star, enabling detailed modelling. Uniquely for the contemporary work, for the first time within a grid-based modelling framework, is the inclusion of fitting directly to the observed individual frequencies of red giants. We find that the increased level of detail in the specialised grids, combined with the constraints from the individual frequencies, results in age estimates for both stars that align with expectations.