Astronomers have found a new type of supernova in a galaxy about 500 million light years away from Earth. This enormous explosion, called a merger-triggered core collapse supernova, was expected to occur in some systems where two stars orbit each another, but had never been seen before.
The most common type of supernova is a core collapse supernova, which happens when a massive star runs out of fuel to burn and collapses. 鈥淭hat鈥檚 a star dying of old age,鈥� says at the California Institute of Technology in Pasadena. 鈥淲hat we found is massive stars can actually die much earlier.鈥�
Dong and his colleagues searched data taken by the Very Large Array Sky Survey in 2017 and 2018 for bright radio-emitting objects that weren鈥檛 present in earlier surveys. They found one blast of radiation that was far brighter than the rest, a source designated J121001+495647. They then took follow-up observations and searched through archival data, ultimately finding a blast of gamma rays that came from the same spot in 2014.
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Combining all this information led the researchers to a clear picture of this object鈥檚 history. Their calculations indicate that it was a massive star orbiting a more compact object, either a neutron star or a black hole, that over time fell into the star and sprayed plasma into a shell of matter around it.
鈥淚magine a really heavy object ploughing through water 鈥� it鈥檚 going to create waves and the water will splash outwards,鈥� says Dong. 鈥淭he same thing happens with the material inside the star.鈥�
Eventually, the compact object disrupted the star鈥檚 core, creating the powerful jet that was observed in 2014. At a slightly slower pace, the entire star exploded, causing a shock wave through the shell of matter that in turn created the radio waves that led Dong and his colleagues to look into this explosion.
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