A giant ‘hiccuping’ star in its final stages before exploding has been spotted by a team of international astronomers.
The once in a blue moon event only happens to stars between 60-150 times the size of the sun, and has been theorised by researchers but never actually seen before.
Scientists are hoping that observing the phenomenon will help provide major breakthroughs in human’s understanding of how large stars operate and their role in shaping the universe.
The team named the process ‘Pulsational Pair Instability’ (PPI), which sees molten cores at the centre of large stars rapidly expand and contract before exploding, producing a sort of ‘hiccuping’ effect.
When this process happens, shell material ejects from the star and strips down the star’s core. These shells can collide with eachother, which produces powerful bursts of light.
Lead author Dr Charlotte Angus, from the Astrophysical Research Centre (ARC) at the Queen’s University in Belfast, said the shell collisions are much fainter than the final supernova explosion, meaning it had previously not been possible to confirm the theory.
She added: ‘In December 2020, we identified a new bright supernova, now named “SN2020acct”, in a nearby spiral galaxy called NGC 2981. The light from SN2020acct disappeared pretty quickly.
‘But then in February 2021, we saw light coming from the same region of the galaxy again.
‘This is very unusual as supernovae normally don’t reappear.’
Telescopes from Hawaii, Chile, South Africa and the US were used by the team of astronomers to help track the supernova, which spotted it twice.
The first time it appeared, light created from slow-moving shells of material colliding near the star were confirmed by astrophysicists as an example of PPI.
The second time it showed up, the supernova was expanding at a faster rate, indicating that its core exploded, marking the end of its life.
Dr Matt Nicholl, from the ARC at Queen’s University, concluded: ‘There’s still a lot we don’t know about massive stars but confirming Pulsational Pair Instability as a real thing is a major step forward in knowledge and greater understanding of these amazing cosmic events’.
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