Astronomers find huge black hole in Milky Way

PARIS: Astronomers identified the largest stellar black hole yet discovered in the Milky Way, with a mass 33 times that of the Sun, according to a study published yesterday.

The black hole, named Gaia BH3, was discovered “by chance” from data collected by the European Space Agency’s Gaia mission, said an astronomer from the National Centre f or Scientific Research (CNRS) at the Observatoire de Paris, Pasquale Panuzzo.

Gaia, which is dedicated to mapping the Milky Way galaxy, located BH3 2,000 light years away from Earth in the Aquila constellation.

As Gaia’s telescope can give a precise position of stars in the sky, astronomers were able to characterise their orbits and measure the mass of the star’s invisible companion — 33 times that of the Sun.

Further observations from onthe-ground telescopes confirmed that it was a black hole with a mass far greater than the stellar black holes already in the Milky Way.

“No one was expecting 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,” Mr Panuzzo said.

The stellar black hole was discovered when scientists spotted a “wobbling” motion on the companion star that was 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,” Mr Panuzzo said.

Stellar black holes are created from the collapse of massive stars at the end of their lives and are smaller than supermassive black holes whose creation is still unknown.

Such giants have already been detected in distant galaxies via gravitational waves. But “never in ours”, said Mr Panuzzo.

BH3 is a “dormant” black hole and is too far away from its companion star to strip it of its matter and therefore emits no X-rays, making it hard to detect.