Supermassive news as search

IT APPEARS that a whole population of miniature black holes might be lurking in the cosmos, waiting to reveal their secrets.

The discovery came after a group of astronomers developed a new way to search for black holes.

These cosmic entities – with a gravitational pull so strong not even light can escape – can form when massive stars collapse at the end of their life. The stellar black holes discovered so far have a mass at least five times that of the Sun.

If the dying star is below a certain mass, however, it will collapse into a small, dense neutron star. These stars are generally no bigger than about twice the mass of the Sun – any bigger, and they’d collapse into a black hole. This leaves a gap between the biggest neutron stars and the smallest black holes, which has remained unfilled – until now. The new technique makes use of the fact that black holes can often be found in a binary system – two stars locked in mutual orbit.

When one star dies and becomes a black hole, it can stay in the system, its presence revealed by changes in the living star’s light spectrum as it orbits its invisible companion.

The international team used data from APOGEE (Apache Point Observatory Galactic Evolution Experiment), which collected light spectra from 100,000 stars across the Milky Way. The team concentrated on 200 stars that looked like they might be orbiting a black hole.

Further data-crunching then revealed a giant red star orbiting a low-mass black hole, estimated to be about 3.3 times the mass of the Sun. ‘We’ve come up with a