Mystery Of The Zombie Star That Won’t Die
A brightly burning ‘zombie‘ supernova that refuses to die has left astronomers baffled.
The star, which lies half a billion light years away, has exploded numerous times since 1954.
This has stumped astronomers as supernovas are generally considered to explode just once and standard theoretical models cannot explain its behaviour.
Researchers at Las Cumbres Observatory in Goleta, California, have been studying the phenomenon, which was first observed in 2014 by the Intermediate Palomar Transient Factory telescope near San Diego.
In January 2015 the event, known as iPTF14hls, was classified as a type II-P supernova, which results from the rapid collapse and violent explosion of a single massive star.
This type of supernova gives off a distinctive flash and tend to stay bright for around 100 days and supernovae lasting more than 130 days are extremely rare.
But iPTF14hls remained bright for almost two years (600 days), with the brightness of the light it emitted varying by up to 50 per cent over this time, as if it were exploding over and over again.
The evolution of the event also seems to be taking place roughly ten times slower than others of its type.
Adding to the puzzle, telescope imagery uncovered by the team suggests explosions may have taken place at the same location in 1954.
Supernovae are known to explode only once, shine for a few months and then fade, but iPTF14hls experienced at least two explosions, 60 years apart.
Writing in an opinion piece for the journal Nature, Stan Woosley, a professor of astronomy at the University of California, Santa Cruz, said of the findings.
“As of now, no detailed model has been published that can explain the observed emission and constant temperature of iPTF14hls, let alone the possible eruption 60 years before the supernova. ”
“A better understanding could provide insight into the evolution of the most massive stars, the production of the brightest supernovae and possibly the birth of black holes that have masses near 40 solar masses, such as those associated with the first direct detection of gravitational waves.”
“For now, the supernova offers astronomers their greatest thrill: something they do not understand.”
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