Analysis of Newly Cataloged Open Star Cluster UPK 220 with Gaia DR3 and TESS: Discovering Member Variable Stars

Studies on star clusters with the same age and initial chemical composition have gained momentum in recent years with the use of Gaia. In addition, the discovery of new clusters with Gaia has increased the number of open clusters (OCs) to be examined. Many of these discovered sources are intermediate-age OCs and have not been analyzed in detail yet. In this study, we focused on newly cataloged OC UPK 220. The fundamental parameters (distance, age, metallicity and reddening) of UPK 220 were determined by analysing the variable stars within the cluster, while simultaneously constraining the parameters of the variable stars using these cluster parameters. To achieve this, we combined GaiaDR3 and TESS photometric observations. Using GaiaDR3, we derive fundamental parameters of UPK 220 through membership analyses, and with TESS, we discovered eight member variable stars. We also extracted the atmospheric parameters (log g, [Fe/H] and Teff) for the variable stars using SED, GSP-Phot and GSP-Spec, and MESA models.