Planets in Stellar Clusters Extensive Search. V. Search for planets and identification of 18 new variable stars in the old open cluster NGC 188

TL;DR

This study conducted a long-term search for transiting planets in the old open cluster NGC 188, resulting in no planet detections but the discovery of 18 new variable stars and detailed light curves.

Contribution

It provides extensive observational data on NGC 188, including the first identification of 18 variable stars and high-precision light curves over 15 months.

Findings

No transiting planets detected in NGC 188

Discovered 18 new variable stars

Provided high-precision light curves over 15 months

Abstract

We have undertaken a long-term project, Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. In this paper we present the results for NGC 188, an old, rather populous cluster. We have monitored the cluster for more than 87 hours, spread over 45 nights. We have not detected any good transiting planet candidates. We have discovered 18 new variable stars in the cluster, bringing the total number of identified variables to 46, and present for them high precision light curves, spanning 15 months.