AstroSat Explores NGC 5053’s Stellar Populations

(ORDO NEWS) — Using the AstroSat spacecraft, Indian astronomers examined the galactic globular cluster known as NGC 5053.

Globular clusters (GCs) are closely related stars that orbit galaxies. Globular clusters can help researchers better understand the history of formation and evolution of early-type galaxies, since the emergence of globular clusters seems to be closely related to periods of intense star formation.

At a distance of about 57,000 light-years from Earth is NGC 5053 – one of the most metal-poor galaxy clusters.

Although NGC 5053 was discovered in 1784, nearly 150 years later it was confirmed as a globular cluster. This was mainly due to the high latitude of the cluster, the abundance of faint stars, and the presence of variable stars.

Now, to shed more light on the stellar composition of NGC 5053, a team of astronomers led by Kolencheri Jeetendran Nikitha of the Indian Institute of Space Science and Technology in Kerala, India, have decided to observe the cluster with the Ultra Violet Imaging Telescope (UVIT) aboard AstroSat. The study was complemented by data from ESA’s Gaia satellite.

The team was able to catalog 1,884 ultraviolet stars in NGC 5053 and photometry them. By analyzing the proper motion of these stars from the Gaia data, they were able to determine the composition of this cluster.

According to the results of the study, NGC 5053 has a significant population of blue horizontal branch stars, which is typical for metal-poor GCs.

In addition, astronomers have identified stellar population candidates that have not been identified by previous observations, including 14 blue strangler (BSS) candidates and one extreme horizontal branch (EHB) star.

The researchers noted that the radial distribution and spectral energy distribution (SED) of the BSS population in NGC 5053 suggest that they occurred as a result of a collision.

This scenario is consistent with previous speculations indicating the possibility of a BSS collision originating in low-density clusters like NGC 5053.

In addition, the study showed that the metallicity of NGC 5053 is -1.9, and its age is estimated at about 12.5 billion years.


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