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Astronomers discover an unusual, rare star formed by an immense explosion


A hypernova, 10 times more powerful than a supernova explosion, may’ve given rise to an unusual star in our galaxy.


ESO/SpaceEngine/L. Calçada

Thanks to a bunch of astronomer-detectives in Australia, you can add this wild phrase to your lexicon today: Magnetorotational hypernova. 

Do you need that in a sentence? Sure, I can help. “A magnetorotational hypernova may be to blame for the mysterious chemical composition of star SMSS J200322.54-114203.3.” 

All right, all right, all right — let’s stop right there and go back in time to make sense of all this.

In the very early years of the universe, some 13 billion years ago, there was a star. There were many stars, in fact, but this particular star was huge and born only of hydrogen and helium. It was also spinning rapidly and had a very strong magnetic field. As it began to run out of fuel, its time as a star came to an end. Its last breath was violent. The star collapses in on itself and explodes: this is a magnetorotational hypernova — an explosion about 10 times as energetic as your bog-standard supernova.

The only reason we know of its existence is because of a new study, published in the journal Nature on Wednesday, that examined the star SMSS J200322.54-114203.3 (or just J2003-1142, for short). Analyzing J2003-1142, researchers found that it contains very low amounts of iron, a sign it likely came from a primordial star that had exploded, but it also contains a strange variety of heavy elements that aren’t usually found in such stars. 

“We calculate that 13 billion years ago J2003-1142 formed out of a chemical soup that contained the remains of this type of hypernova,” said David Yong, an astrophysicist at Australian National University. “No one’s ever found this phenomenon before.” 

Researchers hypothesize that J2003-1142 rose like a phoenix from the ashes of an ancient, exploding star. Lying about 7,500 light-years from Earth, J2003-1142 is practically a cosmic neighbor. It was identified by Australian researchers from a sample of over 600 million objects in the SkyMapper survey, which took place at the Siding Spring Observatory in New South Wales, Australia. Further observations of J2003-1142 were gathered with the Very Large Telescope in Chile.

The observations allowed researchers to examine J2003-1142’s chemical composition in great detail. 

“The chemical elements we see in J2003-1142 were produced by a progenitor (i.e., parent) star, and the chemical composition of J2003-1142 holds clues to the characteristics of that parent,” Yong said.

J2003-1142 displayed a lot of unusual features: high nitrogen, high zinc and large amounts of heavy elements like uranium. These act almost like fingerprints for the astro-detectives, revealing how its parent star lived and died and giving researchers the first hint that a magnetorotational hypernova was to blame for J2003-1142’s weird composition.

In the past, scientists have speculated that these heavier elements are created when neutron stars collide. Increasing evidence suggests that those collisions alone aren’t enough to explain where some of the heaviest elements come from. The modeling performed by Yong and colleagues suggests a magnetorotational hypernova might help explain the difference. 

“This is an extremely important discovery that reveals a new pathway for the formation of heavy elements in the infant universe,” said Lisa Kewley, director of Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (Astro 3D).



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