Scientists have discovered an example of a black hole that should be extremely common, but quite hard to find.
The problem of detecting what astronomers call dormant black holes occurs because these objects are not actively feeding on matter such as gas, dust, or stellar material lifted from a companion star. Without power, these black holes don’t emit the X-rays that scientists use to detect typical black holes. The new discovery could have implications for understanding how stars crumble at the end of their lives, according to the researchers.
“We found a needle in a haystack,” said Tomer Shenar, an astrophysicist at the University of Amsterdam in the Netherlands and lead author of the new study. statement (will open in a new tab) .
Connected: 8 Ways to Know if Black Holes Really Exist
Shenar and colleagues have discovered a stellar-mass black hole, about nine times the mass of the sun, located in the Tarantula Nebula, a star-forming region in our galaxy. Large Magellanic Cloud. The black hole revolves around a huge blue star with a mass equivalent to 25 suns; this duo makes up a binary system called VFTS 243.
Even though billions of dormant black holes are expected to exist in almost every galaxy, this is the first unequivocal detection of a dormant stellar-mass black hole outside of a galaxy. Milky Way.
This black hole may be extraordinary for another reason. Stellar-mass black holes usually form when massive stars run out of fuel needed to continue nuclear fusion. The end of the merger also ends the outward pressure that keeps the star from total gravitational collapse. The subsequent so-called core collapse is usually accompanied by a powerful cosmic explosion. supernova which blows away the outer layers of the star.
However, the situation with the black hole in VFTS 243 seems to be different, with no visible signs of the supernova that accompanied the collapse of the star.
“The star that formed the black hole in VFTS 243 appears to have completely collapsed without any sign of a previous explosion,” Shenar said. “Evidence for this ‘outright collapse’ scenario is recent, but our study provides perhaps one of the most direct indications. This has huge implications for the origin of black hole mergers in space.”
“Black Hole Police”
The discovery of such a black hole by this particular group of scientists may come as a surprise to the astronomical community.
The team usually works to disprove the existence of potential black holes rather than confirm them. This trend has earned the crew the jocular nickname “black hole police”, and co-author Karim El-Badri of the Harvard and Smithsonian Institutions’ Center for Astrophysics called Shenar a “black hole destroyer”.
“When Tomer [Shenar] asked me to double-check his conclusions, I had doubts,” El-Badri said. “But I couldn’t find a plausible explanation for the data that didn’t include a black hole.”
The discovery of VFTS 243 required the team to scrutinize six years of data. Very large telescope (VLT), which is located in the Atacama Desert region of northern Chile. In this data, the scientists examined 1,000 massive stars in the Tarantula Nebula region in the Large Magellanic Cloud to see if any of these stars could have a dormant black hole companion.
For each star, the team analyzed its spectrum, which measures how much light the star emits at given wavelengths. And in the VFTS 243 data, the researchers noticed quirks in the star’s orbit that could be caused by a compact but massive companion.
However, the “black hole police” leaves room for other scientists to take on their usual role.
“Of course, I expect others in the field to take a close look at our analysis and try to develop alternative models,” El-Badri said.
The group’s findings are discussed in paper (will open in a new tab) published Monday (July 18) in the journal Nature Astronomy..
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