Analysis Of The Colour-Magnitude Diagram Of The Open Cluster NGC 5822 Based On Observations Using The Itera Robotic Telescope Ahmad Habibi Syah (a), Hakim L. Malasan (b), Muhammad Isnaenda Ikhsan (a*)(b)
a) Department of Atmospheric and Planetary Science, Institut Teknologi Sumatera, Jalan Ters. Ryacudu, Lampung Selatan, Indonesia
*isnaenda.ikhsan[at]sap.itera.ac.id
b) Department of Astronomy, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
Abstract
Star clusters, groups of stars formed from a common nebular cloud, offer key insights into star formation, evolution, and properties like age, distance, and metallicity. In this research, a Colour-Magnitude Diagram (CMD) was constructed from observations using the ITERA Robotic Telescope (IRT) with Bessel B and V filters. Isochrone fitting was then applied to the CMD, producing a theoretical curve that represents the evolutionary stages of stars in the cluster and enables the extraction of key physical parameters. The target of this study is the open cluster NGC 5822, notable for its relatively young age and moderately high metallicity, characteristics that make it especially interesting for stellar and planetary formation studies. Based on the results of the isochrone fitting, the metallicity of NGC 5822 is found to be 0.013 \pm 0.001 ([Fe/H] = -0.137). Referring to the study by Debra A. Fischer and Jeff Valenti on the relationship between metallicity and exoplanet occurrence, clusters with a metallicity similar to NGC 5822 are estimated to have approximately 2\% of their stars hosting exoplanets. Isochrone fitting indicates that NGC 5822 lies at a distance of 529.91 \pm 18.07 parsecs, with a log(age) of 9.098 \pm 0.009, corresponding to an age of 1.256 billion years, and an interstellar extinction of 0.19 \pm 0.138.
Keywords: Stars, Open Cluster, NGC 5822, Colour-Magnitude Diagram (CMD), Isochrone
