It is the smallest confirmed black hole to date and is close to Earth: The “unicorn” was discovered by researchers because it changed a large star.
Columbus, Ohio - Researchers at Ohio State University have now been delighted to discover a small black hole that is closer to the earth than any other previously listed.
Because their find is so special and is also in the constellation Monoceros, i.e. unicorn, the black hole was also given the name "Unicorn".
Black Hole: Created from an exploded star
According to experts' estimates, the little “unicorn” weighs around three times as much as the sun - which is actually very small for a black hole. Black holes are created when massive stars have reached the end of their life and explode in a supernova. The core of the star then, depending on its mass, either collapses into an extremely dense neutron star or it becomes a black hole. So far, however, it has not been clarified where the boundary between the two developments lies and how small the smallest black holes can be.
In addition to its relatively small mass, the newly found “unicorn” is characterized above all by the fact that it is only 1,500 light years away from Earth in the Milky Way, closer than any other before.
In fact, the researchers led by PhD student Tharindu Jayasinghe came across the inactive black hole by chance - it is actually not only visually, but also invisible to the astronomers' measuring devices.
Black hole “unicorn”: this is how it was discovered by researchers
What is visible, however, is its much larger companion: the little "unicorn" is in the orbit of a well-known red giant. The giant star V723 Mon itself is a well-documented object that Jayasinghe and his team took another closer look at because it is always changing. "When we looked at the data, this black hole - the 'unicorn' - just stuck out," quoted the science
magazine scitechdaily as quoting
the doctoral student.
The invisible “unicorn” revealed its existence by the fact that it clearly influenced the shape of the clearly visible giant.
"Just as the moon's gravity affects the oceans on Earth, causing them to bulge towards or away from the moon and produce high waves, so the black hole deforms the star into a football-like shape," says Todd Thompson, who is a co-author on the study.
From the changes in the red giant, the researchers concluded that the black hole existed and were able to determine an approximate size of the “unicorn”.
Smallest black hole independently confirmed
In the meantime, the discovery of the “unicorn” has been confirmed by another, independent research team: Kento Masuda and Teryuki Hirano at the Japanese University of Osaka also came to the conclusion that the “unicorn” distorts its companion - and that the black hole is actually very small should be.
(eu)