The black hole, dubbed LB-1, was spotted by researchers from the National Astronomical Observatory of China. Located 15,000 light-years form Earth, the black hole has an enormous mass 70 times greater than the sun.
Professor Liu Jifeng, who led the study, said: “Black holes of such mass should not even exist in our Galaxy, according to most of the current models of stellar evolution.
“We thought that very massive stars with the chemical composition typical of our Galaxy must shed most of their gas in powerful stellar winds, as they approach the end of their life.
“Therefore, they should not leave behind such a massive remnant. LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation.”
Milky Way’s centre was ripped apart in violent explosion 3.5 million years ago
Until recently, stellar black holes could only be discovered when they gobbled up gas from a companion star, meaning most black holes went undetected.
However, the researchers developed a new way to detect black holes, by looking for stars that orbit an invisible object, puled by its gravity.
This new technique allowed the researchers to detect LB-1, and to understand the black hole’s physical parameters.
The results revealed that the black hole has 70 times the mass of the sun, and has a start eight times heavier than the Sun orbiting it.
Professor David Reitze, from the University of Florida, said: “This discovery forces us to re-examine our models of how stellar-mass black holes form.
“This remarkable result along with the LIGO-Virgo detections of binary black hole collisions during the past four years really points towards a renaissance in our understanding of black hole astrophysics.”