A revised age of the Methuselah star from stellar evolution models with tailored abundances

Context: HD140283 is a metal-poor subgiant and key benchmark for Population II stars. Its proximity and precise observations make it ideal for testing stellar age determinations. It is also one of the oldest known stars and there is some debate about its age as various previous works found an age in conflict with the age of the Universe. Aims: We aim to redetermine its age using updated astrometric, spectroscopic, and seismic data, and assess the impact of chemical composition and stellar evolution model assumptions. Results: Using a revised astrometric parallax from Gaia (π = 16.26 ± 0.026 mas) and dedicated abundances and opacity tables, we inferred an age of 13.08 ± 0.85 Gyr (Guillaume et al. 2024), and, including the asteroseismic data, we provide a preliminary updated value of 12.23 ± 0.51 Gyr. These results highlight the importance of considering non-solar mixtures and seismic constraints to study such old stellar populations.