New variable stars in the field of open cluster NGC188

TL;DR

This study identifies 18 new variable stars in the old open cluster NGC 188 through photometric observations in R and I bands, expanding knowledge of stellar variability in this cluster.

Contribution

It reports the discovery of 18 new variable stars and characterizes their variability types using a novel data processing approach with Astrokit.

Findings

18 new variable stars discovered

Characterization of variability types for each star

Identification of a previously known variable's parameters

Abstract

A photometric study of variable stars in the field of old open cluster NGC 188 is discussed. Observations were carried out in two bands R and I for 5513 stars up to R = 17 mag in the field of 1.5 x 1.5 grad. around the cluster. The photometric data were processed by the console application "Astrokit", which corrects brightness variations associated with the variability of atmospheric transparency and carries out searching for variable stars. We found 18 new variable stars and determined the parameters of one previously known variable. Among discovered stars one is a low-amplitude pulsating variable, one is a EW eclipsing binary, six are eclipsing variables of EA type, five objects are long period variables, and for five stars variability type remains uncertain.