Indian astronomers examined NGC 5053, a galactic globular cluster, using the AstroSat satellite. The findings of the study, which were published on the arXiv pre-print portal on May 27, shed light on the star population of this cluster.
Globular clusters (GCs) are clumps of stars orbiting galaxies that are firmly bonded together. They are viewed by astronomers as natural laboratories for studying the evolution of stars and galaxies. The birth of globular clusters appears to be tightly tied to periods of vigorous star formation, which could help researchers better comprehend the creation history and evolution of early-type galaxies.
NGC 5053 is one of the most metal-poor galactic GCs, orbiting the Earth at a distance of around 57,000 light years. Although NGC 5053 was identified in 1784, it was only verified as a globular cluster nearly 150 years later. The cluster’s high latitude, abundance of dim stars, and existence of variable stars all contributed to this.
Now, a team of astronomers led by KolencheriJithendranNikitha of the Indian Institute of Space Science and Technology in Kerala, India, has decided to observe NGC 5053 with the Ultra Violet Imaging Telescope (UVIT) onboardAstroSat in order to learn more about its stellar content. Data from the ESA’s Gaia satellite was used to supplement the research.
The researchers noted, “In this study, we provide the photometric investigation of the globular cluster NGC 5053 utilizing the UVIT FUV [far-ultraviolet] and NUV [near-ultraviolet] filters in combination with Gaia observations.”
The team was able to create a catalogue of 1884 UV stars in NGC 5053 and perform photometry on them. They were able to identify members of this cluster by evaluating the proper velocity of these stars using Gaia data.
NGC 5053 has a large population of blue horizontal branch (HB) stars, which is typical of metal-poor GCs, according to the study. In addition, the researchers discovered 14 blue straggler star (BSS) candidates and one extreme horizontal branch (EHB) star that had previously gone undetected by earlier investigations. The observations also allowed the researchers to distinguish between known populations of BSSs, as well as BHB stars, RR-Lyrae stars, and SX Phoenicis (SX-Phe) stars.
The radial distribution and spectral energy distribution (SED) of the BSS population of NGC 5053 appear to point to a collisional origin, according to the researchers. This theory is consistent with prior theories suggesting that BSSs in low-density clusters like NGC 5053 could have a collisional origin.
NGC 5053 also has a metallicity of -1.9, and its age is believed to be around 12.5 billion years, according to the study.