Hubble just witnessed the birth of a black hole for the first time. But astronomers didn’t expect this kind of unusual birth.
Usually, when a massive star expands its fuel, its core collapses into a dense object. Thus, sending the rest of its gas outward in an event is called a supernova.
However, this was not the case for a star in a galaxy 22 million light-years away from us. We are talking about the NGC 6946 also known as the “Fireworks Galaxy”.
Rather than exploding into a supernova before collapsing into a black hole, this giant star skipped the drama and went straight to the collapse. The star collapsed straight into a black hole.
Supernovae are a thing in this galaxy and that’s why astronomers call it the “Fireworks Galaxy”. NGC 6946 produces an unusually high rate of supernovae compared to our Milky Way galaxy.
Observing the Event
Starting in 2009, one of its stars named N6946-BH1 brightened just a bit – but then had disappeared from the most advanced telescopes by 2015.
For the first time in recorded history, humans were watching the astronomical phenomenon, reports a team from NASA, Ohio State, and Caltech. And astronomers are calling this event a “massive fail”. This could explain why we have observed so few massive stars going supernova, researchers conducting a new study explained.
“The typical view is that a star can form a black hole only after it goes supernova,” Christopher Kochanek, a co-author on the paper and an astronomer at Ohio State University, said in a statement. “If a star can fall short of a supernova and still make a black hole, that would help to explain why we don’t see supernovae from the most massive stars.”
The team used the Hubble and Spitzer space telescopes, the Large Binocular Telescope, and a variety of other methods to try and get a glimpse of the vanished star, as they describe in the Monthly Notices of the Royal Astronomical Society. But there wasn’t even any infrared radiation that marked the spot where the star had been. Therefore, proving it wasn’t hidden behind a dust cloud or blocked by another object out in space, they said.
The dying star was about 25 times as massive as Earth’s sun.
Thumbnail image: This pair of visible-light and near-infrared Hubble Space Telescope photos shows the giant star N6946-BH1 before and after it vanished out of sight by imploding to form a black hole. Credit: NASA, ESA, and C. Kochanek (OSU)