European Southern Observatory (ESO) astronomers are astonished to find the closest black hole from Earth. The researchers are saying if you are in the Southern Hemisphere, you can observe this black hole with the naked eye at night. The reason one can so easily view it is that it is only a thousand light-years away from us!
Petr Hadrava is the co-author of the paper published in Astronomy & Astrophysics, which discusses this black hole. He is a scientist at the Academy of Sciences of the Czech Republic, Prague. He explains how the team was surprised to realize that they had found the first stellar system with a black hole that can be observed from Earth unaided.
This relatively dark black hole was rather difficult to spot for the scientists. Black holes are known to flare up when they feed on their companion stars’ matter, which reveals their location to the astronomers. But this particular one did not exhibit such behavior. So it had to be spotted only by tracking its gravitational effect on 2 nearby stars. ESO’s La Silla Observatory in Chile found this black hole with its 2.2-meter telescope.
The researchers were initially observing this HR 6819 system for its 2 very closely spaced stars. One of those stars was orbiting a black every 40 Earth days. So the researchers studied its trajectory to conclude that the black hole was quite big.
“An invisible object with a mass at least 4 times that of the Sun can only be a black hole,” Thomas Rivinius, lead author and ESO scientist, said in the statement.
The handful of black holes discovered in our Milky Way were all discovered with the help of the bright flashes of X-rays they gave away when they were interacting with their environment. But the way our closest black hole was discovered, by studying its gravitational effects, means there are many more such black holes we can now find with this method.
Astronomers are trailing another system LB-1 which they believe also has 3 bodies like the HR 6819. LB-1 is further from Earth than HR 6819 but still relatively close, said another co-author of the paper, Marianne Heida.
Image credit: ESO/L. Calçada