Discoveries in other galaxies are considered “needles in a haystack.”
Astronomers have found what they are calling a “cosmic needle in a haystack” in a galaxy that is adjacent to our own Milky Way. This “needle in a haystack” is a black hole that is not only considered to be dormant, but also appears to have been born without the explosion of a star that was in its final stages of life.
Researchers stated on Monday that this one is different from all other known black holes in that it is “X-ray quiet,” meaning that it does not emit powerful X-ray radiation that is indicative of gobbling up nearby material with its strong gravitational pull, and that it was not born in a stellar explosion known as a supernova.
Black holes are extremely dense objects having a gravitational pull that is so strong that not even light can escape from them. This one, which was discovered in the Tarantula Nebula region of the Large Magellanic Cloud galaxy and is approximately 160,000 light years away from Earth, has a mass that is at least nine times higher than that of our sun. One light year is equal to 9.46 trillion kilometres, which is the distance that light travels in one year.
Through a marriage of stars, this black hole is married to an incredibly brilliant and hot blue star with a mass approximately 25 times that of the sun. Together, they orbit in space. The name given to this purportedly binary system is VFTS 243. The researchers have a theory that the companion star may someday turn into a black hole as well and that it might combine with the existing one.
Because they have such limited interaction with their surroundings, dormant black holes, which are assumed to be very widespread, are notoriously difficult to spot. After further investigation, a great number of the previously suggested options were shown to be false, including by members of the team that discovered this one.
Tomer Shenar, a research fellow in astronomy at Amsterdam University and the primary author of a study that was published in the journal Nature Astronomy, noted that the difficulty is in locating the objects in question.
“We found a needle in a haystack,” you may say.
“After astronomers have been searching for decades, it’s the first object of its kind discovered,” said astronomer and study co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics. “It’s the first object of its kind discovered after astronomers have been searching for decades.”
The observations spanning six years were taken by the Very Large Telescope, which is located in Chile and is operated by the European Southern Observatory.
There are several distinct types of black holes. The smallest black holes, such as the one that was just found, are known as stellar-mass black holes. They are generated when huge individual stars, which have reached the end of their life cycles, collapse into themselves. In addition to the giant supermassive black holes that reside at the centres of most galaxies, there are also black holes of intermediate mass. These black holes are found throughout the universe.
“Darkness is an essential property of black holes as an object type. They do not produce any visible light at all. As a result, in order to find a black hole, we typically look at binary systems. In these systems, we observe one luminous star moving around a second object that we have not yet found “Julia Bodensteiner, a postdoctoral research fellow at the European Southern Observatory in Munich and a co-author on the study, was quoted as saying.
In most cases, a large supernova explosion is presumed to be related with the collapse of huge stars into black holes in scientific literature. In this particular instance, a star with a mass around 20 times that of our sun expelled some of its material into space during the final stages of its life, and then quietly fell in on itself without producing an explosion.