Onionlike Space Explosion May Be a New Type of Supernova
But astronomers had never seen definitive proof of this occurring deep inside stars. Researchers have now discovered a star about two billion light-years from Earth that shed its onionlike layers down to its heaviest material before exploding, hinting at where we came from.
'We know over 10,000 supernovas, but we detected a supernova that is very, very different to anything we've observed before,' said Steve Schulze, an astrophysicist at Northwestern University and the lead author of the paper describing the discovery, published Wednesday in Nature. 'We had no idea it's possible to strip a star to this extreme amount.'
Dr. Schulze and his team discovered the supernova, called SN 2021yfj, from data collected by the Zwicky Transient Facility survey run at the Palomar Observatory in California. Additional observations using the Keck Observatory in Hawaii helped pick apart the explosion's light and the elements that were released.
Dr. Schulze and his team estimated the star to have been about 60 times the mass of our sun — quite a big one. Usually when a star dies, astronomers observe a jumble of elements from its guts mixed together and flung into the cosmos. But for some reason, this one's layers were stripped away over thousands of years before it exploded.
This is important because it gives a hint of the star's layered structure, something never seen before. Scientists have long thought stars have onionlike layers. The outer layers, made of lighter elements like hydrogen and helium, give way to increasingly heavier chemicals like carbon, oxygen, magnesium, silicon, sulfur, argon and, finally, iron at the star's core.
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