Space

Birth of a black hole witnessed as star vanishes without a bang

Birth of a black hole witnesse...
A star that disappeared before astronomers' eyes could mark the first time the birth of a black hole has been directly witnessed
A star that disappeared before astronomers' eyes could mark the first time the birth of a black hole has been directly witnessed
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A star that disappeared before astronomers' eyes could mark the first time the birth of a black hole has been directly witnessed
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A star that disappeared before astronomers' eyes could mark the first time the birth of a black hole has been directly witnessed

For the first time, astronomers have witnessed a star disappear right before their eyes. Known as N6946-BH1, the star appears to have collapsed into a black hole without the usual flair of a supernova, which not only marks the first time scientists have witnessed the birth of a black hole, but could change our understanding of the life and death of stars.

According to conventional thinking, when a star exhausts its energy supply, it violently ejects most of its matter outwards in a supernova, before collapsing in on itself to form a black hole. But N6946-BH1 has bucked the trend, skipping the supernova stage and quietly collapsing into a black hole. These failed supernovae (or "massive fails", as the team calls them) could help patch some holes in our stellar knowledge.

"The typical view is that a star can form a black hole only after it goes supernova," says Christopher Kochanek, lead researcher on the study. "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."

Some 22 million light-years from Earth, the star N6946-BH1 is located in (or used to be, anyway) the galaxy NGC 6946, which is often known as the Fireworks Galaxy due to how regularly its stars go supernova. But this one was different. Telescope images show that N6946-BH1 was clearly visible in 2007, brightened slightly around 2009, and had vanished completely by 2015.

To confirm that a dust cloud or something similar hadn't just obscured their view, the astronomers examined the spot in the visible light spectrum with the Hubble Space Telescope, and in infrared with Spitzer, and came up empty in both cases. N6946-BH1 was simply gone.

With a mass 25 times that of the Sun, the resulting supernova should have been clearly visible. Instead, that minor brightening may have been a failed supernova, which would be the first time one has been directly detected. If stars can collapse in this way, the team says, it could help explain why supernovae from particularly massive stars are rarely spotted.

"N6946-BH1 is the only likely failed supernova that we found in the first seven years of our survey," says Scott Adams, co-author of the study. "During this period, six normal supernovae have occurred within the galaxies we've been monitoring, suggesting that 10 to 30 percent of massive stars die as failed supernovae."

The research was published in the Monthly Notices of the Royal Astronomical Society, and the team discusses the find in the video below.

Source: Ohio State University

9 comments
piperTom
The quote has the astronomer "suggesting that 10 to 30 percent of massive stars die as failed supernovae." Making statistical inferences from a single event is just bizarre.
Bob
OOOH. Artist conceptions, speculation and ONE example. I think we have another premature theory in the works. As I recall from my astronomy physics courses, most stars are not large enough to go supernova and many aren't even large enough to go nova. While I believe this is the source of dark matter, that's another discussion. It could be this star is just being eclipsed by a larger dark companion, an extremely dense dust cloud or its light refracted away from our view by another black hole between here and there. I'm beginning to think astrophysicists are like weathermen. They seem to get paid whether they are right, wrong or just guessing.
Tanstar
It's an alien star eating technology. They are coming for us! :)
*Joe*
Or the star was harvested by aliens
MK23666
Reading comments about scientific discoveries these days is like going to a horse race ... There is a lot of whinnying and naying.
Tom Swift
Or it was eaten by an enormous mutant star-goat.
ChrisWalker
or it could have just experienced a event that disrupted its spin-kinetic energy and its energy simply disipated like when a spinning top slowly stops, or a fidget toy slowly stops, or a gyroscope slowly stops. dozens of reasons why a small stars energy dissipates without obsessed with still not proven black hole existence. what is this obsession with black holes and dark energy? none of it is proven and just wishing for its existence and trying to force its magical creation wont make it real. Santa Clause isnt real no matter how many children wish it.
CarlMagrath
The aliens are building an Intergalatic Freeway and they'd just removed the planet by destroying it and using the debris as ballast for their spaceships. This theory has long been supported as it was first spoken in the novel, Hitchhikers Guide to the Galaxy. It won't be long now before Earth must pay the Piper
b@man
I saw this first hand in about 1978. The star collapsed and it took about 3 seconds total. Amazing site.