An inactive, invisible black hole, which is four times the mass of the Sun, has been discovered by the scientists by observing a strange star orbiting it. Researchers said this is the first such inactive stellar-mass found in a globular star cluster.
Globular star clusters are huge spheres of thousands of stars that orbit most galaxies. The oldest known stellar systems in the Universe date back to the beginning of the galaxy growth and evolution. More than 150 systems are currently known to belong to the Milky Way.
One particular cluster, NGC 3201, situated in the southern constellation of Vela, was discovered to be behaving oddly by the researchers.
Benjamin Giesers from European Southern Observatory, said, “It was orbiting something that was completely invisible, which had a mass more than four times the Sun - this could only be a black hole! The first one found in a globular cluster by directly observing its gravitational pull.”
The clusters, due to their large masses and great ages, are thought to have produced a large number of stellar-mass black holes which exploded and collapsed over the long lifetime of the cluster.
ESO’s MUSE instrument provides astronomers with unique ability to measure the motions of far away stars at same time.
The researchers have for the first time detected an inactive black hole at the heart of a globular cluster.
From the observed properties, the star was said to be about 0.8 times the mass of the Sun, and the mass of its mysterious counterpart was recorded to be 4.36 times the mass of the Sun, which was almost as equal as the mass of a black hole.