The White Dwarf Age of NGC 2477

TL;DR

This paper determines the age of the open cluster NGC 2477 using deep HST photometry and introduces a new Bayesian method for more accurate age estimation by fitting multiple stellar parameters simultaneously.

Contribution

It presents a novel Bayesian statistical technique for deriving cluster ages, improving accuracy over traditional isochrone fitting methods.

Findings

White dwarf age of NGC 2477 is approximately 1.035 Gyr.

The Bayesian method yields consistent results with main sequence turnoff ages.

The approach enhances precision in cluster age determination.

Abstract

We present deep photometric observations of the open cluster NGC 2477 using HST/WFPC2. By identifying seven cluster white dwarf candidates, we present an analysis of the white dwarf age of this cluster, using both the traditional method of fitting isochrones to the white dwarf cooling sequence, and by employing a new Bayesian statistical technique that has been developed by our group. This new method performs an objective, simultaneous model fit of the cluster and stellar parameters (namely age, metallicity, distance, reddening, as well as individual stellar masses, mass ratios, and cluster membership) to the photometry. Based on this analysis, we measure a white dwarf age of 1.035 +/- 0.054 +/- 0.087 Gyr (uncertainties represent the goodness of model fits and discrepancy among models, respectively), in good agreement with the cluster's main sequence turnoff age. This work is part of our ongoing work to calibrate main sequence turnoff and white dwarf ages using open clusters, and to improve the precision of cluster ages to the ~5% level.