# Age determination for 269 $Gaia$ DR2 Open Clusters

## TL;DR

This study utilizes Gaia DR2 data and Bayesian isochrone fitting to accurately determine ages, distances, and extinctions for 269 open clusters, enhancing our understanding of Galactic disk properties.

## Contribution

It introduces an automated Bayesian method for precise age and parameter estimation of open clusters using Gaia data, improving upon previous techniques.

## Key findings

- Derived ages, distances, and extinctions for 269 open clusters.
- Selected low-reddening, non-very young clusters for reliable age estimation.
- Demonstrated the effectiveness of Gaia data combined with Bayesian isochrone fitting.

## Abstract

$Context$. 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 a better understanding of the disc 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 make use of the membership determination based on the precise Gaia astrometry and photometry. We apply anautomated 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.