Globular cluster 47 Tucanae. Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.Astronomers have examined the brightest star in a globular cluster called 47 Tucanae (also known as NGC 104). The study published on August 3rd by arXiv.org provides important insight into the star's properties and chemical composition, which could help us better understand the nature of the cluster.Globular clusters are collections of tightly bound galaxies orbiting stars. These clusters are seen by astronomers as natural laboratories that allow for the study of the evolution of stars, galaxies, and galaxies. Because of their close relationship to periods of intense star-formation, globular clusters may help researchers to better understand the formation history of early type galaxies and the evolution of the early types.It is located 13,000 light-years away in the constellation Tucana. 47 Tucanae or 47 Tuc, or short for 47 Tuc, is a globular cluster that has a diameter of approximately 120 light years. It can be seen naked and is the second-brightest GC in all of the sky.The "Bright Star" (BS) is the brightest star in 47 Tuc, at both optical and ultraviolet wavelengths. It is a blue giant star of spectrum type B8 III, with an effective temperature around 11,000 K.Although there have been many studies on the bright star, it is not yet fully understood what its chemical composition looks like. The Bright Star is a unique window into 47 Tuc's chemistry. A team of astronomers led William V. Dixon from the Space Telescope Science Institute Baltimore, Maryland investigated the star using the Far Ultraviolet Spectroscopic Explorer, the Hubble Space Telescope, and the Magellan Telescope.These observations enabled the team to determine the photospheric abundances for 26 elements in the bright star. Data show that intermediate-mass elements scale with iron, while heavy elements have approximately solar abundances. The star's carbon-to-nitrogen ratio was low, which suggests it is part of the second generation. It also has a low carbon to oxygen ratio, which indicates that it was not subject to third dredge-up on the AGB.The fundamental parameters of the bright stars were determined by the study. It has a radius around 9.63 solar radiations, a mass of approximately 0.54 Solar masses, and an effective temperature of 10,850 K. This is slightly less than the loss of single stars on the AGB.The researchers concluded that the brightness star did not experience any significant changes in its photosphere abundances when it climbed the AGB.The paper's authors added, "If so then its heavy-element abundances would be typical of cluster values."Further explorations of the Globular Clusters NGC 1261 & NGC 6934 are available.More information: William V. Dixon et al, Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104), arXiv:2108.01641 [astro-ph.SR] William V. Dixon et al, Observations of the Bright Star in the Globular Cluster 47 Tucanae (NGC 104), arXiv:2108.01641 [astro-ph.SR] arxiv.org/abs/2108.016412021 Science X Network
