The Clusters AgeS Experiment (CASE): Variable Stars in the Globular Cluster 47 Tucanae

TL;DR

This study analyzed over 5400 images of 47 Tucanae, discovering 21 new variable stars, including eclipsing binaries and X-ray counterparts, expanding knowledge of the cluster's variable star population.

Contribution

The paper presents the discovery of 21 new variable stars in 47 Tuc, including detached eclipsing binaries, based on extensive imaging data collected over 12 years.

Findings

21 new variable stars identified, including 4 eclipsing binaries.

New variables mostly located outside the cluster core.

Two detached binaries identified as promising for follow-up.

Abstract

Based on over 5400 BV images of 47 Tuc collected between 1998 and 2010 we obtained light curves of 65 variables, 21 of which are newly detected objects. New variables are located mostly just outside of the core in a region poorly studied by earlier surveys of the cluster. Among them there are four detached eclipsing binaries and five likely optical counterparts of X-ray sources. Two detached systems are promising targets for follow-up observations. We briefly discuss properties of the most interesting new variables.