Investigating Open Cluster KING 6: Detection of Three New Variables

This study presents a photometric analysis of the intermediate-age open cluster King 6, utilizing photometric data in 𝑈𝐵𝑉(𝑅𝐼)𝑐 passbands and 𝐽𝐻𝐾𝑠 from the 2𝑀𝐴𝑆𝑆 mission. Gaia DR3 kinematic data were used to estimate the membership probabilities, and 𝑇𝐸𝑆𝑆 data were employed to search for variable stars within the cluster. The cluster’s radius is estimated to be 9.′0 based on the stellar density profile, while optical and near-infrared color-color diagrams revealed color excesses of 𝐸(𝐵 − 𝑉) = 0.58 ± 0.03, 𝐸(𝐽 − 𝐾) = 0.24 ± 0.03, and 𝐸(𝑉 − 𝐾) = 1.53 ± 0.01 mag. The interstellar extinction law is normal in the direction of the cluster. The cluster′s estimated age is ∼251 Myr and the distance is 724 ± 5 pc. The mass function slope was found to be 𝑥 = 0.57 ± 0.28 by considering stars ≥ 1 M⊙. Our analysis indicates that the cluster was dynamically relaxed. Furthermore, we identified three new variable stars for the first time in the cluster region using 𝑇𝐸𝑆𝑆 data. These variables belong to the category of slow-pulsating B-type variables with periods of 46.70, 47.92, and 37.56 h.