The European Space Agency’s (ESA) XMM-Newton observatory has discovered the best-ever candidate for a very rare type of cosmic phenomenon: a medium-weight black hole in the process of shredding a nearby star.
A team of researchers using data from ESA’s XMM-Newton X-ray space observatory, as well as NASA’s Chandra X-ray telescope, have seen a rare sign of activity. They detected a vast flare of radiation in the outskirts of a distant galaxy, thrown off as a star passed too close to a rare black hole and was subsequently devoured.
According to ESA, there are various types of black holes throughout the Universe: massive stars create stellar-mass black holes when they die, while galaxies host supermassive black holes at their centres, with masses equivalent to millions of Suns.
Between these extremes is another member of the black hole ‘family’, these are intermediate-mass black holes. Thought to eventually grow to become supermassive, these black holes are especially elusive, and very few have ever been found.
How does this type of rare black hole form?
This type of black hole is thought to form in various ways. One formation scenario is the runway merger of massive stars lying within a dense star cluster, making the centres of these clusters one of the best places to search for them.
However, by the time these black holes have formed, the sites tend to be devoid of gas, leaving the black holes with no material to consume and little radiation to emit, making them difficult to spot.
Lead scientist Dacheng Lin of the University of New Hampshire, USA said: “One of the few methods we can use to try to find an intermediate-mass black hole is to wait for a star to pass close to it and become disrupted — this essentially ‘activates’ the black hole’s appetite again and prompts it to emit a flare that we can observe.
“This kind of event has only been clearly seen at the centre of a galaxy before, not at the outer edges.”
The scientists believe that the star was disrupted and torn apart by a rare black hole with a mass of around fifty thousand times that of the Sun.