MYSTERIOUS ZOMBIE STAR KEEPS EXPLODING, BUT WON’T DIE
Morrissey was right – there is a light that never goes out! An international team of astronomers has made a bizarre discovery: a star that has exploded repeatedly, yet carries on shining.
When stars of a certain size reach the end of their lifecycle, they explode in energetic cosmic events known as supernovae. Such explosions have been recorded by astronomers thousands of times, and in every recorded case, such an explosion has marked the death of a star. But now scientists seem to have found an exception in iPTF14hls, a supernova that has exploded at least twice in the past 70 years.
“This supernova breaks everything we thought we knew about how they work. It’s the biggest puzzle I’ve encountered in almost a decade of studying stellar explosions,” said Dr Iair Arcavi of Las Cumbres Observatory.
iPTF14hls was discovered in 2014 by researchers at Caltech. At first it appeared normal, but seven months after it faded it began growing in brightness. When astronomers went back and looked at archival data, they found evidence of an explosion in 1954 at the same location. The star has somehow survived the first explosion, only to explode again in 2014.
One potential explanation has to do with the star’s mass. Having at least 50 times the mass of our Sun, it could have been big enough to be the first example of a theorised event known as a Pulsational Pair Instability Supernova – a star so massive and hot that it created antimatter at its core, which in turn caused it to undergo repeated explosions.
“This is one of those head-scratcher type of events,” said Dr Peter Nugent. “At first we thought it was completely normal and boring. Then it just kept staying bright, and not changing, for month after month. I would really like to find another one like this.”
Supernovae are supposed to only happen once, but try telling iPTF14hls that