Astronomers from the European Southern Observatory (ESO) have discovered a new black hole, the closest to Earth ever detected, located in a stellar system visible to the naked eye. It is "only" 1,000 light years from our planet, according to a study published this Wednesday in the journal Astronomy & Astrophysics .
This stellar black hole is the result of the collapse of a massive star on itself, as big as at least four times the Sun. Unlike supermassive black holes, it is "silent" because it "does not interact violently with its environment" (it does not absorb matter). It is therefore “really black” and hidden in the star system “HR 6819”, specifies ESO in a press release.
A team of astronomers from the European Southern Observatory (ESO) and other institutes discovered a black hole located only 1,000 light years from Earth.
Illustration credit: @ESO / L. Calçada https://t.co/FiolIpUdUW pic.twitter.com/Urm4gVdhYH
"The closest black hole to Earth"
Initially, scientists were interested in HR 6819 as a binary star system, which includes a variety of stars more massive and brighter than the Sun. Thanks to the "FEROS" spectrograph located at the La Silla observatory (Chile), astronomers have noticed that one of the two stars moves faster than the other, and orbits in an unusual way, every forty days, around of an invisible object.
By studying this trajectory, they were able to detect the presence of the black hole, and calculate its mass. "An invisible object with a mass at least four times the Sun can only be a black hole," says astrophysicist Thomas Rivinius, the study's lead author. "This star system contains the closest black hole to Earth that we know of," he said. "We were totally surprised when we realized that it was the first stellar system visible to the naked eye with a black hole", adds Petr Hadrava, from the Prague Academy of Sciences, co-author of the study .
Better understand the sources of gravitational waves
For the moment, only two dozen black holes have been detected in our galaxy, which includes in its center a supermassive black hole. "We know few stellar black holes in the Milky Way, but we think there are a lot, because they are natural products of the evolution of massive stars", comments Pierre Kervella, astronomer of the Paris Observatory - PSL, interviewed by AFP. “As long as they are calm, that is to say that there is no accretion of matter, these objects are difficult to detect. If they are not in a system, we cannot see them, ”he continues.
The black hole of HR 6819 could thus be discovered via "the gravitational attraction which it imprints on the star", decrypts the astronomer, according to which this study is an "additional brick to understand the sources of gravitational waves" , detected in 2016.
Science
Milky Way: The black hole discovered by scientists in our galaxy "should not exist"
Science
A black hole is believed to be the source of the largest explosion observed in the universe
- Discovery
- Scientists
- Astronomy
- Black hole
- Science