An amateur astronomer caught a supernova on camera during the explosion’s earliest moments, giving physicists a glimpse of a long-sought phase of stellar death.
Víctor Buso spotted the supernova from his rooftop observatory in Rosario, Argentina, on September 20, 2016, when he aimed his telescope straight overhead at spiral galaxy NGC 613 to test a new camera. To avoid letting in too much light from the city sky — Rosario is a city of about 1.2 million people — he took a series of about 100 images that were each exposed for 20 seconds, spanning about an hour and a half.
Over the last half-hour of Buso’s observations, the supernova appeared and then doubled in brightness. In 2013, astronomers spotted a supernova within hours of its explosion (SN Online: 2/13/17), but this is one of the first to be spotted before it exploded.
Because there is no way to predict when and where a supernova will go off, this sort of observation is extremely rare, says astrophysicist Melina Bersten of the National University of La Plata in Argentina, who reports details of the supernova in the Feb. 22 Nature.
“This is completely unusual, and was something that many people were searching for around the world without success,” Bersten says. “It was incredible.”
Bersten and her colleagues analyzed the light from the supernova and found that it matches models of the first phase of a supernova called the shock breakout phase, in which a shock wave from a massive star’s collapse ricochets back from the star’s core and pushes stellar material outward.