Variable Stars in the Globular Cluster M14

TL;DR

This study used image subtraction to identify and classify variable stars in globular cluster M14, confirming known variables and discovering 71 new ones, including RR Lyrae stars and a contact binary.

Contribution

The paper introduces a new survey of M14 using image subtraction, discovering 71 new variable stars and providing detailed classifications and periods for these variables.

Findings

Confirmed 62 known variables in M14.

Discovered 71 new variable stars, including RR Lyrae and a contact binary.

Provided periods and classifications for all identified variables.

Abstract

Using an image subtraction method we have searched for variable stars in the globular cluster M14. We confirmed 62 previously known catalogued variables. In addition to the previoulsy known variables we have identified 71 new variables. We have confirmed the periods of most of the cataloged variables with just a few exceptions. Of the the total number of confirmed variables, we found a total of 112 RR Lyrae stars, several of which exhibited the Blazhko Effect. Of the total we classified 55 RR0, 57 RR1, 19 variables with periods greater than 2 days, a W UMa contact binary, and an SX Phe star. We present the periods of previously found variables as well as the periods, classification, and lightcurves of the newly discovered variables.