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

TL;DR

This study combines Gaia DR3 and TESS data to analyze the newly cataloged open star cluster UPK~220, determining its fundamental parameters and discovering eight member variable stars to enhance understanding of intermediate-age clusters.

Contribution

It introduces a comprehensive method integrating Gaia and TESS data to analyze a newly cataloged open cluster and identify its variable stars, providing detailed stellar parameters.

Findings

Determined fundamental parameters of UPK~220 using Gaia data.

Discovered eight new member variable stars with TESS.

Extracted atmospheric parameters for variable stars using multiple models.

Abstract

Studies on star clusters with the same age and initial chemical composition have gained momentum in recent years with the use of \textit{Gaia}. In addition, the discovery of new clusters with Gaia has increased the number of open clusters to be examined. Many of these discovered sources are intermediate-age open clusters and have not been analyzed in detail yet. In this study, we focused on newly cataloged open cluster 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 ($logg$, $[Fe/H]$ and $T_{\rm eff}$) for the variable stars using SED, GSP-Phot and GSP-Spec, and MESA models.