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Astronomers have observed an explosion 180 million light years away which challenges our current understanding of explosions in space, that appeared much flatter than ever thought possible
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Explosions are almost always expected to be spherical, as the stars themselves are spherical, but this one is the flattest ever seen
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The explosion observed was an extremely rare Fast Blue Optical Transient (FBOT) - known colloquially amongst astronomers as 鈥渢he cow鈥 - only four others have ever been seen, and scientists don鈥檛 know how they occur, but this discovery has helped solve part of the puzzle
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A potential explanation for how this explosion occurred is that the star itself may have been surrounding by a dense disk or it may have been a failed supernova
An explosion the size of our solar system has baffled scientists, as part of its shape - similar to that of an extremely flat disc - challenges everything we know about explosions in space.
The explosion observed was a bright Fast Blue Optical Transient (FBOT) - an extremely rare class of explosion which is much less common than other explosions, such as supernovas. The first bright FBOT was discovered in 2018 and given the nickname 鈥渢he cow鈥.
Explosions of stars in the universe are almost always spherical in shape, as the stars themselves are spherical. However, this explosion, which occurred 180 million light years away, is the most aspherical ever seen in space, with a shape like a disc emerging a few days after it was discovered. This section of the explosion may have come from material shed by the star just before it exploded.
It鈥檚 still unclear how bright FBOT explosions occur, but it鈥檚 hoped that this observation, published in Monthly Notices of the Royal Astronomical Society, will bring us closer to understanding them.
Dr Justyn Maund, Lead Author of the study from the University of 含羞草传媒鈥檚 Department of Physics and Astronomy, said: 鈥淰ery little is known about FBOT explosions - they just don鈥檛 behave like exploding stars should, they are too bright and they evolve too quickly. Put simply, they are weird, and this new observation makes them even weirder.
鈥淗opefully this new finding will help us shed a bit more light on them - we never thought that explosions could be this aspherical. There are a few potential explanations for it: the stars involved may have created a disc just before they died or these could be failed supernovas, where the core of the star collapses to a blackhole or neutron star which then eats the rest of the star."
What we now know for sure is that the levels of asymmetry recorded are a key part of understanding these mysterious explosions, and it challenges our preconceptions of how stars might explode in the Universe
Dr Justyn Maund
Department of Physics and Astronomy, University of 含羞草传媒
Scientists made the discovery after spotting a flash of polarised light completely by chance. They were able to measure the polarisation of the blast - using the astronomical equivalent of polaroid sunglasses - with the Liverpool Telescope (owned by Liverpool John Moores University) located on La Palma.
By measuring the polarisation, it allowed them to measure the shape of the explosion, effectively seeing something the size of our Solar System but in a galaxy 180 million light years away. They were then able to use the data to reconstruct the 3D shape of the explosion, and were able to map the edges of the blast - allowing them to see just how flat it was.
The mirror of the Liverpool Telescope is only 2.0m in diameter, but by studying the polarisation the astronomers were able to reconstruct the shape of the explosion as if the telescope had a diameter of about 750km.
Researchers will now undertake a new survey with the international Vera Rubin Observatory in Chile, which is expected to help discover more FBOTs and further understand them.
