The UNICORN

The recent discovery of “Unicorn” , the smallest and the closest black hole found so far may lead to help solve an enduring mystery in astrophysics.

“Unicorn” orbits with a red giant star about 1500 light-years from Earth. Named “Unicorn” in part because it is unique, and in part, because it was found in the constellation Monoceros, named by the ancient astronomers after the Greek word for Unicorn.

How was the Unicorn found?

The usual way used to discover black holes is detecting the radiation emitted by the accretion disk formed around the black hole due to the heating up of material with X-ray telescopes. However, the astronomers of Ohio State University have deviated from this convention. A method used to search exoplanets which can be extremely hard to spot directly was their new approach. Measuring periodic changes in the brightness and spectrum of light coming from a red giant star known as V723 Mon, the data from a number of observatories contributed to the discovery of the Unicorn.

Although Unicorn is distorting the red giant into a raindrop shape, it isn’t pulling material off it. This means that an accretion disk does not form. This in turn, makes the Unicorn to go unnoticed as X ray emmission does not occur. This is a strong indicator to be the reason behind the lessened discovery of small black holes.

The study of “Unicorn” and such others will help to get a clearer picture of the fate of the stars. Either they will collapse to become black holes, or will explode as a supernova to become a neutron star. This will also help scientists who are still unable to figure out the behaviour of matter at nuclear densities to riddle out this cosmic puzzle.

What will be the next chapter?

Astronomers are eagerly waiting for the next data release from the Sloan Digital Sky Survey. This uses a telescope in New Mexico to provide detailed looks at millions of celestial objects, and so may reveal the motion of stars as they respond to unseen companions. The Vera C. Rubin Observatory, now under construction in Chile, may also find small black holes in the future.

As more data becomes available, astronomers hope to learn whether the shortage of little black holes points to some novel aspect of stellar physics – or if small black holes are in fact peppered throughout the galaxy, uncounted thus far because we’ve only just developed the means to hunt for them.

Why is the Unicorn important to Sri Lankans?

‘When we looked at the data, this black hole – the Unicorn – just popped out,‘ said lead author Tharindu Jayasinghe, a doctoral student in astronomy at The Ohio State University and an Ohio State Presidential Fellow.
Ohio State News

A proud Sri Lankan, Tharindu Jayasinghe, a doctoral student in astronomy from Ohio State University, is the lead author of the team that went on to discover the Unicorn. This will be an invaluable stimulus for the future of Sri Lankan young astronomy explores.