This project implements and empirically validates a scalable seismic diagnostic for stellar mass and age inference in early red giant branch stars. Rather than developing a new inference scheme from scratch, the work deploys an existing, physically motivated diagnostic that exploits a structural feature in oscillation frequencies which becomes strongly mass-sensitive following the subgiant phase, as described in this paper.
a) Stellar tracks between 0.7M⊙ and 1.7M⊙ starting at the beginning of core hydrogen burning and ending just before the helium flash or at a stellar age of 12 × 109 years.
b) The grey box in a) shown in detail, in which the plateau features are discernible at all masses shown. The inset shows a typical δν0,2 uncertainty for a star between 1.4M⊙ and 1.5M⊙ observed by Kepler, while typical Kepler Δν uncertainties are negligible in this context.
In this regime, global stellar parameters can be inferred from a limited set of seismic parameters accessible in large numbers from survey-quality data. Calibration is performed using eclipsing binary systems in the early RGB phase with independently determined dynamical masses.
What you will do
- Cross-match eclipsing binary catalogues (DEBCat, LAMOST, ASAS-SN) with stars showing solar-like oscillations from Kepler or TESS
- Calibrate a grid of stellar models against dynamical masses from eclipsing binary systems
- Quantify systematic offsets relative to existing seismic scaling-relation estimators
- Contribute to a publicly released asteroseismic inference tool
Skills you will develop
Asteroseismic data analysis, stellar modelling, large catalogue cross-matching, Bayesian inference.
Expected outcomes
The calibrated tool will be made publicly available and the resulting benchmark sample of ~50 early RGB stars will enable population-scale inference of stellar parameters with tight uncertainty estimates, deployable to hundreds of TESS targets.
BEACON aims to establish an empirically calibrated framework linking stellar oscillation properties to independently measured stellar masses, radii, and ages across post-solar evolutionary phases. By anchoring survey-scale seismic measurements to benchmark stars with dynamical masses and interferometric radii, the project will enable precise, model-independent stellar ages to be derived for evolved stars throughout the Milky Way.
If you want to know more, please get in touch via email.