Science

A star is not born: Indian scientists spot odd occurrence in distant galaxy

M Ramesh Chennai | Updated on January 08, 2020 Published on January 08, 2020

Draw international attention to hydrogen cloud with no star formation

A team of scientists at the National Centre for Radio Astrophysics, Pune, that was looking into a distant galaxy, chanced upon an odd occurrence that made it sit bolt upright and exclaim, ‘What!’

The extremely big (380,000 light years across) ring of hydrogen around a galaxy named AGC 203001 is only the second such ring ever to be discovered, after a similar ‘Leo ring’ that was found in 1983.

Clouds of hydrogen, the first and the simplest of elements, whose atom has just one proton and one electron, abound in the universe. However, two aspects about the hydrogen ring around AGC 203001 puzzle the scientists. First, even though this cloud rings the galaxy, it is well removed, which is odd — usually the gas ring hugs its galaxy.

The second is even more intriguing — there was no new star formation. A simple axiom in astronomy is, where there is hydrogen cloud, there is star birth. This is because atoms in the hydrogen clouds come together due to gravity and fuse, causing mind-boggling amounts of heat and light — called ‘star’. As the atoms crush into each other further, some of the gas gets expelled out and forms a ring.

Hydrogen ring

Yet, in this case, no matter how keenly the scientists peered into it, they couldn’t find any new star being born. “We confirmed this using a very deep optical image taken using the Canada-France-Hawaii Telescope (CFHT) in Hawaii, with the help of two French astronomers; but we did not find any stars in the hydrogen ring,” Omkar Bait, a doctoral research student who, along with Prof Yogesh Wadadekar, discovered the ring, told Business Line.

While all this may not matter much to common people, this is a significant discovery for astrophysicists, and has already received international attention. A few days back, the NCRA, which is one of the laboratories under the Tata Institute of Fundamental Research, put out a press release on the discovery, which said that the scientists used their ‘Giant Metrewave Radio Telescope’ to peer into the galaxy. When the oddity was discovered, they got two French astronomers, Pierre-Alain Duc and Jean-Charles Cuillandre, to confirm it with the CFHT in Hawaii.

Puzzling mystery

The mystery continues to puzzle the scientists; they wonder whether this gas is part of the AGC 203001 galaxy or is the remnant of another galaxy, and why no new star has formed in the galaxy.

This opens up new areas for investigation, the results of which will help us understand better how the universe was formed, and where it is headed. “In future, we will be working on understanding what might have led to the formation of the ring,” Bait said.

The AGC 203001 galaxy is 260 million light years away from the earth, which means that light particles (photons) that hit the scientists’ telescopes started from the galaxy en route to earth even well before dinosaurs were born here.

Published on January 08, 2020
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