Detection and characterisation of oscillating red giants: first results from the TESS satellite

TL;DR

This study demonstrates the potential of TESS asteroseismology combined with Gaia data to precisely determine fundamental properties of red giant stars across the Galaxy, enabling large-scale Galactic archaeology.

Contribution

First ensemble asteroseismic analysis of TESS-observed red giants, showing improved stellar parameter estimates when combining seismic and astrometric data.

Findings

Stellar radii determined to a few percent precision

Stellar masses estimated within 5-10% accuracy

Ages constrained to approximately 20% uncertainty

Abstract

Since the onset of the `space revolution' of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archaeology investigations. The launch of the NASA TESS mission has enabled seismic-based inferences to go full sky -- providing a clear advantage for large ensemble studies of the different Milky Way components. Here we demonstrate its potential for investigating the Galaxy by carrying out the first asteroseismic ensemble study of red giant stars observed by TESS. We use a sample of 25 stars for which we measure their global asteroseimic observables and estimate their fundamental stellar properties, such as radius, mass, and age. Significant improvements are seen in the uncertainties of our estimates when combining seismic observables from TESS with astrometric measurements from the Gaia mission compared to when the seismology and astrometry are applied separately. Specifically, when combined we show that stellar radii can be determined to a precision of a few percent, masses to 5-10% and ages to the 20% level. This is comparable to the precision typically obtained using end-of-mission Kepler data