Stellar ages, masses, extinctions and orbital parameters based on spectroscopic parameters of Gaia DR3

TL;DR

This paper derives stellar ages, masses, extinctions, and orbital parameters for millions of Gaia DR3 stars using spectroscopic and astrometric data, enabling detailed galactic archaeology of the Milky Way.

Contribution

It introduces a method combining spectroscopic, photometric, and astrometric data to estimate stellar parameters and orbits, providing a large, publicly available catalogue for galactic studies.

Findings

Reliable ages for stars younger than 10 Gyr with <50% uncertainty.

Turn-off stars yield the most accurate age estimates.

Uncertainties of ~2 Gyr for giants and main-sequence stars with low extinction.

Abstract

Gaia DR3 provides radial velocities for 33 million stars and spectroscopically derived atmospheric parameters for more than five million targets. When combined with the astrometric data, these allow us to derive orbital and stellar parameters that are key in order to understand the stellar populations of the Milky Way and perform galactic archaeology. We use the calibrated atmospheric parameters, 2MASS and Gaia-EDR3 photometry, and parallax-based distances to compute, via an isochrone fitting method, the ages, initial stellar masses and reddenings for the stars with spectroscopic parameters. We also derive the orbits (actions, eccentricities, apocentre, pericentre and Zmax) for all of the stars with measured radial velocities and astrometry, adopting two sets of line-of-sight distances from the literature and an axisymmetric potential of the Galaxy. Comparisons with reference catalogues of field and cluster stars suggest that reliable ages are obtained for stars younger than 9-10Gyr when the estimated relative age uncertainty is <50%. For older stars, ages tend to be under-estimated. The most reliable stellar type for age determination are turn-off stars, even when the input atmospheric parameters have large uncertainties. Ages for giants and main-sequence stars are retrieved with uncertainties of ~2Gyr when extinction towards the star's line-of sight is smaller than A_V<2.5mag. The full catalogue is made publicly available to be downloaded. With it, the full chemo-dynamical properties of the extended Solar neighbourhood unfold, and allow us to better identify the properties of the spiral arms, to parameterise the dynamical heating of the disc, or to thoroughly study the chemical enrichment of the Milky Way.