Study suggests astronomers discover largest black hole in Milky Way
The black hole, named Gaia BH3, was discovered 'by chance' from data collected by the European Space Agency's Gaia mission
According to a study published Tuesday, astronomers spotted the largest stellar black hole yet discovered in the Milky Way, with a mass 33 times that of the Sun.
The black hole, named Gaia BH3, was discovered "by chance" from data collected by the European Space Agency's Gaia mission, an astronomer from the National Centre for Scientific Research (CNRS) at the Observatoire de Paris, Pasquale Panuzzo, told Agence France-Presse (AFP).
Gaia, dedicated to mapping the Milky Way galaxy, is BH3 2,000 light years away from Earth in the Aquila constellation.
As Gaia's telescope can precisely position stars in the sky, astronomers could characterize their orbits and measure the mass of the star's invisible companion – 33 times that of the Sun.
Further observations from on-the-ground telescopes confirmed it was a black hole with a mass far greater than the stellar black holes already in the Milky Way.
"No one expected to find a high-mass black hole lurking nearby, undetected so far. This is the kind of discovery you make once in your research life," Panuzzo said in a press release.
Scientists discovered the stellar black hole when they spotted a "wobbling" motion in the companion star orbiting it.
"We could see a star a little smaller than the Sun (around 75% of its mass) and brighter, that revolved around an invisible companion," Panuzzo said.
Stellar black holes are formed when massive stars collapse at the end of their lives. They are smaller than supermassive black holes, the creation of which is still unknown.
Such giants have already been detected in distant galaxies via gravitational waves.
But "never in ours," said Panuzzo.
BH3 is a "dormant" black hole too far away from its companion star to strip it of matter. Therefore, it emits no X-rays, making it difficult to detect.
Gaia's telescope identified the first two inactive black holes (Gaia BH1 and Gaia BH2) in the Milky Way.
For the past 10 years, Gaia has operated 1.5 million kilometers from Earth and delivered a 3D map of the positions and motions of over 1.8 billion stars in 2022.
Source: AFP
