STScI/OSU: Collapsing Star Gives Birth to a Black Hole

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STScI/OSU: Collapsing Star Gives Birth to a Black Hole

Post by bystander » Thu May 25, 2017 5:54 pm

Collapsing Star Gives Birth to a Black Hole
NASA | GSFC | JPL-Caltech | Spitzer | STScI | HubbleSite | 2017 May 25
[c][img3="N6946-BH1 Failed Supernova (Artist's Illustration)
Credit: NASA, ESA, and P. Jeffries (STScI)
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[youtube][/youtube]Star Gives Birth to Possible Black Hole in Hubble and Spitzer Images
Credit: NASA/GSFC/SVS/Katrina Jackson
Music Credit: "High Heelz" by Donn Wilerson [BMI] and Lance Sumner [BMI];
Killer Tracks BMI; Killer Tracks Production Music
Astronomers have watched as a massive, dying star was likely reborn as a black hole. It took the combined power of the Large Binocular Telescope (LBT), and NASA's Hubble and Spitzer space telescopes to go looking for remnants of the vanquished star, only to find that it disappeared out of sight.

It went out with a whimper instead of a bang.

The star, which was 25 times as massive as our sun, should have exploded in a very bright supernova. Instead, it fizzled out—and then left behind a black hole.

"Massive fails" like this one in a nearby galaxy could explain why astronomers rarely see supernovae from the most massive stars, said Christopher Kochanek, professor of astronomy at The Ohio State University and the Ohio Eminent Scholar in Observational Cosmology.

As many as 30 percent of such stars, it seems, may quietly collapse into black holes — no supernova required.

"The typical view is that a star can form a black hole only after it goes supernova," Kochanek explained. "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." ...

Among the galaxies they've been watching is NGC 6946, a spiral galaxy 22 million light-years away that is nicknamed the "Fireworks Galaxy" because supernovae frequently happen there — indeed, SN 2017eaw, discovered on May 14th, is shining near maximum brightness now. Starting in 2009, one particular star, named N6946-BH1, began to brighten weakly. By 2015, it appeared to have winked out of existence.

After the LBT survey for failed supernovas turned up the star, astronomers aimed the Hubble and Spitzer space telescopes to see if it was still there but merely dimmed. They also used Spitzer to search for any infrared radiation emanating from the spot. That would have been a sign that the star was still present, but perhaps just hidden behind a dust cloud.

All the tests came up negative. The star was no longer there. By a careful process of elimination, the researchers eventually concluded that the star must have become a black hole. ...

The big star that couldn’t become a supernova
Ohio State University | 2017 May 25
One star’s “massive fail” could help solve a mystery

The Search for Failed Supernovae with the Large Binocular Telescope: Confirmation of a Disappearing Star - S. M. Adams et al
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