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India has already made a big success in the space world with the impressive launch of Chandrayaan-2. Now, Indian scientists have also taken a huge dive in astronomical observations. A team of researchers at Aryabhatta Institute of Observational Sciences (ARIES) have discovered 28 new variable stars in the outer part of our Milky Way galaxy. Thanks to the efforts of Indian researchers, our own galaxy was replenished with another 28 stars.
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ARIES Director Wahab Uddin described the finding of the new variable stars as a “rare achievement”. A variable star is a star whose luminosity or brightness changes.
“It is for the first time that variable stars have been identified in Globular cluster NGC 4147 in the constellation of Coma Berenices, former director of ARIES”, Anil Pande said.
Besides the detection of new variable stars, the study also provides important insights into the internal structure of NGC 4147 which is located closer to the Earth than previously thought, according to Pande.
The stars spotted are nearly 60,000 light-years away in the constellation, Coma Berenices, which is usually visible in the northern night sky. The luminosity of the stars fluctuates from time to time due to changes in the emitted light, with the periodic swelling and shrinking of stars, which ultimately changes the quantum of light reaching Earth.
This is a relatively small globular cluster, ranking 112th in luminosity among the Milky Way globular cluster population, Pande said.
“The halo of a galaxy is a nearly spherical region surrounding the galaxy like diffuse light when seen from a distance. Only about 1% of a galaxy’s mass resides in its halo area, and coupled with low brightness, the observation of stars in halos is very difficult. This is why our finding holds much significance. Also, due to the old age of stars in the halo area of our galaxy, studying stars in this area helps scientists to figure out the evolutionary history of the Milky Way,” said Sneh Lata, a scientist at ARIES.
Globular clusters are very tightly bound by gravity, which gives them their spherical shapes, and relatively high stellar densities towards their centers. Scientists chanced upon these stars as they conducted photometric observations using a powerful 3.6-meter optical telescope, the Devasthal Optical (DOT).
The study was published on May 20 on arXiv, an online archive for research. The detailed findings of the research will be published in the August issue of the Astronomical Journal.
