Astronomers have detected what they call a cosmic “needle in a haystack”: a black hole that is not only classified as latent, but appears to have been born without the explosion of a dying star.
Key points:
- The black hole is about 160,000 light-years from Earth
- Its mass is at least nine times greater than that of our Sun.
- Black holes are extraordinarily dense objects, with such intense gravity that not even light can escape.
The researchers said the black hole, in a galaxy adjacent to the Milky Way, differs from all other known black holes in that it is “silent X-ray,” emitting no powerful X-ray radiation indicating that it has swallowed nearby material with its strong gravitational pull, and was not born in a stellar explosion called a supernova.
Black holes are extraordinarily dense objects, with such intense gravity that not even light can escape.
This, with a mass at least nine times larger than our Sun, was detected in the Tarantula Nebula region of the Large Magellanic Cloud galaxy, and is about 160,000 light-years from Earth. A light year is the distance light travels in a year, about 9.5 trillion kilometers.
The newly discovered black hole and an extremely bright, hot blue star with a mass about 25 times that of our Sun are orbiting each other, creating a “binary system” called VFTS 243. Researchers believe the accompanying star it will also end him. become a black hole, which could merge with the current one.
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Latent black holes, which are thought to be relatively common, are difficult to detect because they interact very little with their environment. Numerous candidates proposed above have been denied after a subsequent study, including team members who discovered this one.
“The challenge is to find these objects,” said Tomer Shenar, a researcher in astronomy at the University of Amsterdam and lead author of the study published in the journal Nature Astronomy.
“We identified a needle in a barn.”
“It’s the first object of its kind discovered after astronomers have been searching for decades,” said study astronomer and co-author Kareem El-Badry of the Harvard and Smithsonian Center for Astrophysics.
The researchers used six years of observations from the Very Large Telescope at the Southern European Observatory.
There are different categories of black holes. The smallest, such as the recently detected, are the so-called black holes of stellar mass, formed by the collapse of massive individual stars at the end of their life cycles. There are also intermediate-mass black holes, as well as the huge supermassive black holes that reside in the center of most galaxies.
“Black holes are intrinsically dark objects. They do not emit any light. Therefore, to detect a black hole, we usually look at binary systems in which we see a bright star moving around a second undetected object,” he said. Julia Bodensteiner, co-author of the study, postdoctoral researcher at the European Southern Observatory in Munich.
The collapse of massive stars in black holes is usually assumed to be associated with a powerful supernova explosion. In this case, a star perhaps 20 times the mass of our Sun blew part of its material into space in its agony, then collapsed on itself without any explosion.
The shape of its orbit with its companion also provides evidence of the lack of explosion.
“The orbit of the system is almost perfectly circular,” Dr. Shenar said.
If a supernova had occurred, the force of the explosion would have fired the newly formed black hole in a random direction and given an elliptical orbit instead of a circular one, he added.
Black holes can be “ruthless devourers,” devouring any material (gas, dust, and stars) that wanders within their gravitational pull.
“Black holes can only be voracious without mercy if there is something close enough to be able to devour them. We usually detect them if they are receiving material from an accompanying star, a process we call accretion,” Dr. Bodensteiner said.
Dr. Shenar added: “In so-called latent black hole systems, the companion is far enough away that material does not accumulate around the black hole to heat up and emit X-rays. Instead, the black hole swallow immediately. “
Reuters