Astronomers have discovered one of the smallest black holes on record – and the closest to Earth found to date.
Scientists from Ohio University have discovered one of the smallest black holes in the history of observation, according to the press service of the educational institution. The researchers found their object in the constellation of the Unicorn. The black hole was part of a binary star system: its “companion” was another star – a red giant.
The research results are published by the Monthly Notices of the Royal Astronomical Society.
A black hole is about three times the size of our Sun – a tiny size for a black hole. So far in the Universe, scientists have found very few black holes of this mass. Evidence of their existence was obtained only 1.5 years ago. The object, which scientists have named “Unicorn” is located at a distance of 1,500 light-years from Earth, inside the Milky Way galaxy. The rest of the black holes are much further away. For example, the object in the center of the Milky Way – Sagittarius A * – is 26 thousand light-years distant from Earth. As the authors of the new work note, the tiny black hole “was hidden in plain sight.”
The fact is that the black hole’s companion star is well-documented with telescopes. However, no one carried out the corresponding analysis. After taking measurements, the scientists noticed that something they could not see seemed to revolve around the red giant. As a result, the light from this star changed its intensity and appearance at various points around its orbit.