Variables in Globular Cluster NGC 5024

TL;DR

This study used a 2-m telescope to monitor the globular cluster NGC 5024, discovering approximately eighty new variable stars and revising the properties of known variables, enhancing understanding of stellar variability in this cluster.

Contribution

The paper reports the discovery of about eighty new variable stars in NGC 5024 and updates the classification and periods of previously known variables, using a modified DIA technique.

Findings

Identified 80 new variable stars including SX Phe, W UMa, RR Lyrae, and eclipsing binaries.

Revised periods and statuses of known short-period variables.

Found several variables associated with Blue Straggler Stars.

Abstract

We present the results of a commissioning campaign to observe Galactic globular clusters for the search of microlensing events. The central 10' X 10' region of the globular cluster NGC 5024 was monitored using the 2-m Himalayan Chandra Telescope in R-band for a period of about 8 hours on 24 March 2010. Light curves were obtained for nearly 10,000 stars, using a modified Difference Image Analysis (DIA) technique. We identified all known variables within our field of view and revised periods and status of some previously reported short-period variables. We report about eighty new variable sources and present their equatorial coordinates, periods, light curves and possible types. Out of these, 16 are SX Phe stars, 10 are W UMa-type stars, 14 are probable RR Lyrae stars and 2 are detached eclipsing binaries. Nine of the newly discovered SX Phe stars and two eclipsing binaries belong to the Blue Straggler Star (BSS) population.