In a remote corner of the Milky Way, astronomers have discovered a star that holds the secret of a stellar explosion that occurred billions of years ago, an event so extraordinary that it challenges our current astronomical knowledge.
The star, known as J0931+0038is distinguished by a chemical composition so unusual that it can only be explained as the remnant of a giant star, at least 50 times more massive than our Sunwhich forged the elements before exploding in a supernova (even planets give astronomers trouble).
And here comes the twist: according to current theories, a star of this mass should have collapse directly into a black hole, without passing through the supernova stage and without leaving traces of bizarre elements. “We have never seen anything like it“, says astronomer Alex Ji of the University of Chicago and the Sloan Digital Sky Survey, who led the research.
The star, nicknamed “Barbenheimer” due to its spectacular nucleosynthesis, represents a real enigma for scientists. The chemical composition of J0931+0038 revealed a wealth of elements close to iron, such as nickel and zinc, and a surprising abundance of elements heavier than iron, such as strontium and palladium, much higher than one would expect.
“Sometimes we see one of these features, but we have never seen them all in the same star“, says astronomer Jennifer Johnson of Ohio State University. The research team concluded that most of the metals found in J0931+0038 must come from a single, extremely metal-poor nucleosynthetic source: a star 50-80 times the mass of the Sun that explodedspilled its innards into space and left behind a cloud of material from which J0931+0038 was born.
“Surprisingly, no existing model of element formation can explain what we see“, says astronomer Sanjana Curtis of the University of California, Berkeley, co-leader of the research. “It’s not just a matter of ‘oh, you can adjust something here and there and everything will be fine’ – the whole scheme of elements seems almost self-contradictory.“
Some stars continue to be a mystery to scientists, like these which should be dead but are healthy.