While scientists have observed many supernovas, what occurs immediately before these massive stellar explosions has remained a relative mystery. It’s rare for scientists to observe the death throes of stars. However, recently astronomers observed a star 37 days before it exploded in a massive supernova. The study of this star’s activity over a month before its demise may give scientists new insight on how to predict the death of a star.
Supernovas have their own swan songs. This particular star, observed in August 2010, caught the attention of astronomers because it glowed a bit brighter than usual. A slight brightening like this one indicated a potential supernova, and further investigation confirmed that the star’s core had run out of fuel and collapsed, becoming a type II supernova. A computer program allowed astronomers to detect and analyze this star’s near-death activity. Located at the Palomar Observatory in Southern California, the program sorts through sky survey images from a 48-inch telescope and highlights areas of interest: sudden bright spots among the stars.
The exploded star was 500 million light-years away, but earlier photos brought astronomers immediate information that signaled this ultimate explosion. They spotted another slight brightening 37 days before the supernova occurred. According to astronomers’ calculations, it emitted a shell of gas into space roughly one one-hundredth the mass of the sun at approximately 2,000 kilometers per second.
“The star was making a little burp,” said astronomer Alex Filippenko, according to Science News. This smaller mass reduction before the ultimate mass reduction did not surprise the team observing this star’s death throes.
While it wasn’t a surprise, it was the first time scientists observed such a stellar burp so shortly before a supernova. The correlation before the two events suggested to the team that the smaller mass reductions are 100 times more likely to occur right before a star explodes than at any other point during the star’s existence.
This connection, said Filippenko, could help astronomers detect other supernovas, and may even lead to an incredible feat: not simply detect a star exploding, but predict a supernova before it occurs. “This type of ejection could be a cosmic lamppost for a final explosion that’s about to happen,” he said, according to Science News.
Stars do hurdle mass into space during other times than their supernova swan songs. Eta Carinae, for example, still lives after emitting a shell of gas 10 times the mass of the sun and becoming the night sky’s second-brightest star. While the star hasn’t released matter so intensely since then, astronomers still cannot be sure whether Eta Carinae will continue glowing for years to come or explode in its own supernova in the near future.
More analysis will have to come before astronomers can use the study of this star’s final days to foretell the deaths of other stars.