Scientists find an exotic black hole that is considered a “needle in a haystack”

Scientists find an exotic black hole that is considered a “needle in a haystack”

An artist’s impression showing what the binary star system VFTS 243 – which contains a black hole and a large luminous star orbiting each other – might look like if we observed it up close. (REUTERS)

Estimated reading time: 3-4 minutes

WASHINGTON – Astronomers have discovered in a galaxy next to our Milky Way that they call a cosmic “needle in a haystack” – a black hole that is not only classified as dormant, but appears to have been born without the explosion of a dying star.

Researchers said on Monday that this differs from all other known black holes in that it is “X-ray silent” – and does not emit strong X-rays that indicate devouring nearby material with its strong gravitational force – and that it was not born in a star explosion called a supernova.

Black holes are extraordinarily dense objects with gravity so intense that not even light can escape.

This, with a mass at least nine times larger than our sun, was discovered in the Tarantula Nebula region in the large Magellanic cloud and is located approximately 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 and warm blue star with a mass that is about 25 times larger than the sun orbits this black hole in a star marriage. This so-called binary system is called VFTS 243. The researchers believe that the companion star will eventually also become a black hole and can merge with the other.

Dormant black holes, believed to be relatively common, are difficult to detect because they interact very little with the environment. Numerous previously proposed candidates have been rejected with further studies, including by members of the team that uncovered this.

“The challenge is to find these objects,” said Tomer Shenar, an astronomy fellow at Amsterdam University, lead author of the study, published in the journal Nature Astronomy. “We identified a needle in a haystack.”

“It is the first object of its kind to be discovered after decades of searching by astronomers,” said astronomer and co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics.


It is the first object of its kind to be discovered after astronomers searched for decades.

–Kareem El-Badry, astronomer and co-author


The researchers spent six years observing from the European Southern Observatory’s Chile-based Very Large Telescope.

There are different categories of black holes. The smallest, as the newly discovered, are so-called star-mass black holes formed by the collapse of massive individual stars at the end of their life cycle. There are also medium-sized black holes as well as the huge supermassive black holes that are at the center of most galaxies.

“Black holes are in themselves dark objects. They do not emit any light. Therefore, to detect a black hole, we usually look at binary systems where we see a shining star moving around another, undiscovered object,” said study co-author Julia Bodensteiner, postdoctoral fellow at the European Southern Observatory in Munich.

It is generally believed that the collapse of massive stars into black holes is associated with a powerful supernova explosion. In this case, a star blew some 20 times the mass of the sun some of the material into space in the death battles, and then collapsed into itself without an explosion.

The shape of the track with its companion provides evidence of the lack of an explosion.

“The trajectory of the system is almost perfectly circular,” Shenar said.

Had a supernova occurred, the force of the explosion would have kicked the newly formed black hole in a random direction and given an elliptical rather than circular orbit, Shenar added.

Black holes can be mercilessly voracious and devour all material – gas, dust and stars – that travels within the force of gravity.

“Black holes can only be mercilessly voracious if there is something close enough to devour them. We usually detect them if they receive material from a companion star, a process we call accretion,” Bodensteiner said.

Shenar added, “In so-called dormant black hole systems, the companion is far enough away that the material does not accumulate around the black hole to heat up and emit X-rays. Instead, it is immediately swallowed by the black hole.”

Related stories

The latest science stories

More stories you may be interested in

Leave a Reply

Your email address will not be published.