Astronomers discover unusual and rare star formed by huge explosion

Thanks to a group of astronomer-detectives in Australia, today you can add this crazy phrase to your lexicon: Magneto-rotational hypernova.

Do you need it in a sentence? Of course I can help. “A magneto-rotating hypernova may be the source of the mysterious chemical composition of the SMSS star J200322.54-114203.3.”

All right, very good, very good – let’s stop there and go back in time to make sense of it all.

In the very first years of the universe, some 13 billion years ago, there was a star. There were a lot of stars, actually, but this particular star was huge and was only born from hydrogen and helium. It was also spinning fast and had a very strong magnetic field. As he began to run out of fuel, his time as a star came to an end. His last breath was violent. The star collapses on itself and explodes: it is a magneto-rotating hypernova – an explosion about 10 times more energetic than your standard swamp supernova.

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

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

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

The observations allowed researchers to examine the chemical composition of J2003-1142 in detail.

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

J2003-1142 had many unusual characteristics: high nitrogen content, high zinc content and large amounts of heavy elements like uranium. These act almost like fingerprints to astro-detectives, revealing how her mother star lived and died and giving researchers the first clue that a magneto-rotating hypernova was to blame for J2003-1142’s odd composition. .

In the past, scientists have speculated that these heavier elements are created when neutron stars collide. A growing body of evidence suggests that these collisions alone are not enough to explain where some of the heaviest elements come from. Modeling done by Yong and his colleagues suggests that a magneto-rotational hypernova might help explain the difference.

“This is an extremely important discovery that reveals a new path for heavy element formation in the infantile universe,” said Lisa Kewley, director of the ARC Australian Center of Excellence for Astrophysics. of the sky in 3 dimensions (Astro 3D).