Map identification of NGC 5288 taken from DSS. Credit: Sethi et al, 2023
Located about 7,000 light-years away in the constellation Circinus, NGC 5288 (also known as Cr 278) is a galactic OC discovered in 1835.
By analyzing data from ESA’s Gaia satellite and the Two Micron All Sky Survey (2MASS), Indian astronomers have investigated a galactic open cluster known as NGC 5288. The results of the study, published on May 17 on the preprint server arXiv, return important information regarding the properties of this group. Open Clusters (OCs), formed from the same giant molecular cloud, are groups of stars loosely gravitationally bound to each other. So far, more than 1,000 of them have been discovered in the Milky Way, and scientists are still looking for more, hoping to find a variety of these stellar groupings. Expanding the list of known open galaxy clusters and studying them in detail could be crucial to improving our understanding of the formation and evolution of our galaxy.
Located about 7,000 light-years away in the constellation Circinus, NGC 5288 (also known as Cr 278) is a galactic OC discovered in 1835. It is a rich, strongly absorbed cluster with a small but bright core and an extended corona of low density. Although NGC 5288 has been known for almost two centuries, it is a poorly studied cluster and there are still many discrepancies regarding its fundamental parameters.
Therefore, to shed more light on its properties, a team of astronomers led by Ritika Sethi from the Indian Institute of Scientific Education and Research in Berhampur, India decided to survey this cluster. “We have investigated a little-studied open cluster, NGC 5288, using the 2MASS photometric and astrometric database and Gaia DR3,” the researchers wrote in the paper.
The data allowed the team to calculate the membership probabilities of stars in the field of NGC 5288 and to identify 304 cluster members with a membership probability greater than 50%. In addition, astronomers estimated the cluster’s fundamental properties, investigated its structure, performed a dynamical study, and derived its galactic orbit and orbital parameters.
The study found that NGC 5288 is about 510 million years old and about 9,000 light-years distant, therefore farther than previously estimated. The mean proper motions of the cluster members in right ascension and declination were calculated to be −3.84 and −1.934 mas per year, respectively. The interstellar redness of NGC 5288 was estimated at a level of 0.45.
When it comes to the size of NGC 5288, astronomers found that the core radius and cluster radius are about 1.36 and 5.5 arcminutes, respectively. The slope of the mass function for the cluster was found to be 1.39 for main sequence (MS) stars (within the mass range of 1.0 to 2.7 solar masses). The results also indicate that NGC 5288 is dynamically relaxed.