‘Flattest’ explosion ever seen in space surprises scientists
Image credit: Phil Drury, University of Sheffield
Astronomers have observed an explosion the size of our solar system that was found to be much flatter than ever thought possible.
An explosion the size of our solar system has shocked scientists at the University of Sheffield, due to its unusually flat shape.
The explosion was an extremely rare Fast Blue Optical Transient (FBOT), a type of explosion that was first discovered in 2018 and given the nickname 'the cow'. To date, only four explosions of this class have ever been detected, and its causes are currently unknown.
Explosions are almost always spherical, just like the stars themselves. However, a few days after its discovery, this particular explosion took the shape of a flat disk. It was observed 180 million lightyears away and it has been described as the "flattest" explosion ever detected.
“Very little is known about FBOT explosions – they just don’t behave like exploding stars should, they are too bright and they evolve too quickly," said Dr Justyn Maund, lead author of the study. “Put simply, they are weird, and this new observation makes them even weirder.
“Hopefully, this new finding will help us shed a bit more light on them – we never thought that explosions could be this aspherical."
According to the researchers, a potential explanation for how this explosion occurred is that the star itself may have been surrounded by a dense disk. The explosion could have also been a failed supernova, 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,” Maund said.
The University of Sheffield scientists made the discovery after spotting a flash of a specific wave of light, called polarised light, completely by chance.
The team used the Liverpool Telescope located on La Palma, in the Canary Islands, to analyse the light, allowing them to measure the shape of the explosion, effectively seeing something the size of our solar system but in a galaxy 180 million lightyears away.
The experts then used 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 team 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.
The researchers published their findings in the journal Monthly Notices of the Royal Astronomical Society.
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