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

¹ GEPI, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Paris Cité, 5 place Jules Janssen, 92190 Meudon, France
² LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
³ Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) – UMR 6251, 35000 Rennes, France
⁴ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB), Martí i Franquès, 1, 08028 Barcelona, Spain
⁵ Departament de Física Quàntica i Astrofísica (FQA), Universitat de Barcelona (UB), Martí i Franquès, 1, 08028 Barcelona, Spain
⁶ Institut d’Estudis Espacials de Catalunya (IEEC), Esteve Terradas, 1, Edifici RDIT, Campus PMT-UPC, 08860 Castelldefels (Barcelona), Spain
⁷ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France

^★ Corresponding author; laia.casamiquela@obspm.fr

Received: 26 July 2024
Accepted: 20 October 2024

Abstract

Context. Reliable stellar age estimates are fundamental for testing several problems in modern astrophysics, in particular since they set the timescales of Galactic dynamical and chemical evolution.

Aims. In this study, we determine ages using only Gaia DR3 photometry and parallaxes, in combination with interstellar extinction maps, and spectroscopic metallicities and α 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, and thus we rely on the excellent precision and accuracy of the Gaia photometry.

Methods. 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.

Results. 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 4000 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.