Age determination for 269 Gaia DR2 open clusters
Jordi, C.; Casamiquela, L.; Cantat-Gaudin, T.; Balaguer-Núñez, L.; Vallenari, A.; Soubiran, C.; Heiter, U.; Sordo, R.; Moitinho, A.; Bossini, D.; Bragaglia, A.; Carrera, R.
Italy, Spain, Portugal, France, Sweden
Abstract
Context. The Gaia Second Data Release provides precise astrometry and photometry for more than 1.3 billion sources. This catalog opens a new era concerning the characterization of open clusters and test stellar models, paving the way for better understanding of the disk properties.
Aims: The aim of the paper is to improve the knowledge of cluster parameters, using only the unprecedented quality of the Gaia photometry and astrometry.
Methods: We have made use of the membership determination based on the precise Gaia astrometry and photometry. We applied an automated Bayesian tool, BASE-9, to fit stellar isochrones on the observed G, GBP, GRP magnitudes of the high probability member stars.
Results: We derive parameters such as age, distance modulus, and extinction for a sample of 269 open clusters, selecting only low reddening objects and discarding very young clusters, for which techniques other than isochrone-fitting are more suitable for estimating ages.