Astronomers have found what they are calling a “cosmic needle in a haystack” in a galaxy next to our Milky Way. It is a dormant black hole that seems to have formed without the explosion of a dead star.
Researchers said on Monday that this black hole is different from all the others that we know of because it is “X-ray quiet.” This means that it doesn’t make a lot of X-ray radiation, which would indicate that it is eating nearby matter with its huge gravitational pull, and that it didn’t form in a supernova.
Black holes are very dense things with so much gravity that not even light can get out.
This one was found in the area of the Large Magellanic Cloud galaxy called the Tarantula Nebula. It is about 160,000 light years away from Earth. A light year is the distance light travels in one year, which is 5.9 trillion miles (9.5 trillion km).
In a stellar union, a blue star with a mass about 25 times that of the sun goes around this black hole. VFTS 243 is the name of this so-called binary system. Experts say that the companion star will turn into a black hole in the end and might even merge with the other.
Because they don’t interact much with their surroundings, it’s hard to find black holes that lie dormant for long periods of time. Researchers, including those on the team that found this one, have found problems with many of the candidates that had been suggested before.
“The hard part is finding these objects,” said Tomer Shenar, an astronomy researcher at Amsterdam University and the lead author of the study published in the journal Nature Astronomy. “We found a needle in a bunch of hay. “It’s the first object of its kind to be found after astronomers looked for decades,” said Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics, who also helped write the study.
Researchers used data from the Very Large Telescope at the European Southern Observatory in Chile that went back six years.
There are a lot of different kinds of black holes. As with the newly found black hole, the smallest are what are called “stellar-mass black holes,” which are made when big stars die and fall apart. In the center of most galaxies, there are large supermassive black holes. But there are also black holes with a mass in between.
“Black holes are objects that are always dark. They don’t make any visible light. So, to find a black hole, we usually look at binary systems in which one bright star moves around a second, not-yet-seen object. Julia Bodensteiner, a postdoctoral research fellow at the European Southern Observatory in Munich and co-author of the study, explained this.
Most people think that a huge supernova explosion is linked to the collapse of big stars into black holes. In this case, a star with about 20 times the mass of the sun sent some of its matter into space as it was dying, but it didn’t explode.
The way its orbit with its partner is set up shows that there wasn’t an explosion.
Shenar said, “The system’s path around the sun is almost a perfect circle.”
Shenar pointed out that if there had been a supernova, the power of the explosion would have sent the new black hole into an elliptical orbit instead of a circle.
“Black holes can only be incredibly hungry if there is something close enough for them to eat. “Most of the time, we can find them when they are accreting material from a nearby star,” Bodensteiner said.
Shenar added, “In so-called “dormant” black hole systems, the companion is far enough away that matter doesn’t pile up around the black hole to heat up and give off X-rays. Instead, the black hole swallows it up right away.”
