An artist’s impression showing what the VFTS 243 binary star system might look like, containing a black hole and a large bright star orbiting each other, if we looked at it closely. (REUTERS)
Estimated reading time: 3-4 minutes
WASHINGTON – Astronomers have detected in a galaxy adjacent to our Milky Way 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.
Investigators said Monday that it differs from all other known black holes in that it is “silent X-ray,” which does not emit powerful X-ray radiation indicating that it has swallowed nearby material with its strong gravitational pull, and that it 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, 5.9 trillion miles (9.5 trillion km).
An extremely bright, hot blue star with a mass about 25 times that of the sun orbits with this black hole in a stellar marriage. This so-called binary system is called VFTS 243. Researchers believe that the accompanying star will also become a black hole and could merge with the other.
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 rejected with further studies, including members of the team that discovered this one.
“The challenge is to find these objects,” said Tomer Shenar, a researcher in astronomy at the University of Amsterdam, 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 astronomer and co-author of the Kareem El-Badry study at the Harvard and Smithsonian Center for Astrophysics.
It is the first object of its kind to be discovered after astronomers have been searching for decades.
–Kareem El-Badry, astronomer and co-author of the study
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 provides evidence of the lack of explosion.
“The orbit of the system is almost perfectly circular,” Shenar said.
If a supernova had occurred, the force of the explosion would have propelled the newly formed black hole in a random direction and given an elliptical orbit instead of a circular one, Shenar added.
Black holes can be voracious without mercy, devouring any material (gas, dust, and stars) that wanders within its gravitational pull.
“Black holes can only be voracious without mercy if there is something close enough that they can devour. We usually detect them if they are receiving material from an accompanying star, a process we call accretion,” Bodensteiner said.
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 swallows it immediately. “.
×