Amateur astronomer Victor Buso was testing his camera-telescope setup in Argentina back in September 2016, pointing his Newtonian telescope at a spiral galaxy called NGC613. He collected light from the galaxy for the next hour and a half, taking short exposures to keep out the Santa Fe city lights. When he looked at his images, he realised he’d captured a potential supernova—an enormous flash of light and energy bursting off of a distant star.
The supernova appears on bottom centre-right (Image: Victor Buso)
Buso took more data and informed Argentine observatories, who announced the outcome of their follow-up observations today: “the serendipitous discovery of a newly born, normal type IIb supernova,” according to the paper published in Nature. Not only did this demonstrate the importance of amateur astronomy, but Buso’s images also provided evidence of the brief initial shockwave from the supernova, a phenomenon that telescopes rarely capture, since they’d have to be looking at the exact right place in the sky at the right time.
“This is completely unique,” Melina Bersten, an astronomer from the Instituto de Astrofísica de La Plata in Argentina and first author on the paper, told Gizmodo. “The most exciting thing is this early emission.”
Bersten and her team followed Buso’s observations with monitoring from other telescopes, including the Earth-orbiting Swift telescope, and compared them to earlier data from around the supernova site archived by the Hubble Space Telescope. This work allowed the researchers to categorise the event, now called SN 2016gkg, as a type IIb, or the kind of supernovae thought to involve giant stars ejecting their outer hydrogen layers.
Buso didn’t just discover a supernova, though. He also presented evidence for the “long-sought shock-breakout phase,” as the scientists write, an explosion of energy theorised to emanate from a shock wave at the supernova’s source.
The researchers point out that it’s hard to generalise from a single supernova. There are lots of other sky surveys attempting to do exactly what Buso did: to catch a supernova as it happens. But the paper highlights just how lucky he was: the odds are at least one in a million, “assuming a duration of 1 hour and one supernova per century per galaxy.”
This research also shows that amateur astronomers with a $2,000 piece of equipment can still do impactful work.
“Particularly in a country with no big telescopes around,” Berstein said, “it’s important to be in contact with amateurs who could do many things that are valuable for science.” [Nature]