The black hole, named Gaia BH1, is 10 times more massive than our sun and lies just under 1,600 light-years from Earth. Its companion star has an orbit similar to Earth’s.
A group of astronomers has discovered a black hole that is only about 1,600 light-years away, making it the closest to Earth, according to a study published in the Monthly Notices of the Royal Astronomical Society.
Scientists reported that this black hole, 10 times more massive than our Sun, is located three times closer to the planet than the record holder.
This binary system, named Gaia BH1, was identified by observing the motion of its companion star, which orbits the black hole at the same distance that Earth orbits the Sun.
“Although many systems like this were confirmed to have been detected, almost all of these discoveries have subsequently been disproved,” said the study’s lead author, Kareem El-Badry, of the Harvard-Smithsonian Center for Astrophysics in Massachusetts.
“This is the first unequivocal detection of a Sun-like star in a wide orbit around a stellar-mass black hole in our galaxy,” he added.
The closest black hole to Earth has a companion star
The black hole was initially detected thanks to the Gaia spacecraft of the European Space Agency (ESA). It is found by accurately mapping the positions, velocities and trajectories of some 2 billion stars in the Milky Way.
Black holes are very difficult space objects to identify because they usually have such a strong gravitational absorption field that even light particles cannot escape. For this very reason, Gaia’s companion star BH1 was so important.
The observations “confirmed beyond reasonable doubt that the binary contains a normal star and at least one inactive black hole,” El-Badry said.
“We could not find any plausible astrophysical scenario that could explain the observed orbit of the system, which does not involve at least one black hole,” he added.
Unknowns about its origin
The study team isn’t sure how the star and black hole got to their current positions. For this reason, researchers now seek to know how this system was formed in the Milky Way. Gaia BH1 is located in the constellation Ophiuchus.
The finding “raises many questions about how this binary system formed, as well as how many of these inactive black holes are out there,” he concluded.