This black hole is located just 1000 light-years from us and is part of a triple system with two stars that can be seen with the naked eye.
A team led by astronomers from the European Southern Observatory (ESO) has discovered the closest black hole to Earth ever observed. According to an article published this Wednesday (6) on Astronomy & Astrophysics, the object is located only 1000 light-years from our planet and is part of a triple system that can be seen with the naked eye.
The team was looking at the HR 6819 binary star system when they discovered a third object nearby. Upon analyzing them more deeply, the group found that the two stars orbited an invisible object every 40 days. “This system contains the nearest black hole to Earth that we know of,” said study leader Thomas Rivinius in a statement.
The object is in the constellation of Telescopium and can be seen from the Southern Hemisphere on dark nights with clear skies – even without binoculars or telescopes. “We were totally surprised when we realised that this is the first stellar system with a black hole that can be seen with the unaided eye,” said Petr Hadrava, co-author of the study.
The black hole does not interact violently with its surroundings and therefore looks really “black” when observed. Still, astronomers were able to detect its presence and calculate its mass by studying the orbit of the two stars. “An invisible object with a mass at least 4 times that of the Sun can only be a black hole,” noted Rivinius.
According to the researchers, the discovery of this “silent” black hole suggests that other objects of this type exist in the Milky Way. “There must be hundreds of millions of black holes out there, but we know about only very few,” said Rivinius. “Knowing what to look for should put us in a better position to find them.”
An example is the binary system LB-1, located in the constellation of Gemini. Scientists have long studied the system and have been thinking about the existence of a black hole over there. “By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the Sun and end them in a supernova explosion that leaves behind a black hole,” explained Marianne Heida, one of the researchers, in a statement to the press.