New stellar age estimates using SPInS based on Gaia DR3 photometry and LAMOST DR8 abundances

TL;DR

This paper introduces a new method for estimating stellar ages using Gaia DR3 photometry and LAMOST DR8 spectroscopic data, achieving high accuracy without relying on spectroscopic temperature or gravity measurements.

Contribution

The study presents an improved SPInS code and a novel approach that yields reliable stellar ages for large samples, validated against star clusters.

Findings

Reliable ages for over 35,000 sub-giant stars with <10% uncertainty.

Accurate ages for nearly 244,000 main-sequence turn-off stars.

Method validated on 14 star clusters, confirming reliability.

Abstract

Reliable stellar age estimates are fundamental for testing several problems in modern astrophysics, in particular since they set the time scales of Galactic dynamical and chemical evolution. In this study, we determine ages using only Gaia DR3 photometry and parallaxes, in combination with interstellar extinction maps, spectroscopic metallicities and $\alpha$ abundances from the latest data release (DR8) of the LAMOST survey. In contrast with previous age estimates, we do not use spectroscopic effective temperatures or surface gravities, thus relying on the excellent precision and accuracy of the Gaia photometry. We use a new version of the publicly available SPInS code with improved features, including the on-the-fly computation of the autocorrelation time and the automatic convergence evaluation. We determine reliable age estimates for 35,096 and 243,768 sub-giant and main-sequence turn-off stars in the LAMOST DR8 low- and medium-resolution surveys with typical uncertainties smaller than 10%. In addition, we successfully test our method on more than 4,000 stars of 14 well-studied open and globular star clusters covering a wide range of ages, confirming the reliability of our age and uncertainty estimates.