This Record-Breaking Black Hole Is The Closest To Earth And 10X Bigger Than The Sun
Astronomers have discovered the closest-known black hole to Earth, at just 1600 light-years away. It is also the first clear detection of a dormant stellar-mass black hole in the Milky Way.
Stellar-mass black holes typically weigh in at approximately five to 100 times the mass of our Sun. These types of black holes are quite common, with an estimated 100 million in the Milky Way alone. However, very few stellar-mass black holes have been confirmed as of yet, though almost all are 'active,' or they are easier to detect as they shine brightly in X-rays as they eat up cosmic material from a neighboring stellar companion. This makes finding a dormant black hole, like the one found by astronomers using the International Gemini Observatory, even more incredible.
A group of astronomers were able to detect the new black hole, called Gaia BH1, utilizing the Gemini North telescope operated by NSF's NOIRLab. Its close proximity to Earth is three times closer than the previous record holder, an X-ray binary in the constellation of Monoceros. The discovery was made possible by making observations of the motion of the black hole's companion, a Sun-like star which orbits the black hole at around the same distance as the Earth orbits the Sun.
"Take the Solar System, put a black hole where the Sun is, and the Sun where the Earth is, and you get this system," remarked Kareem El-Badry, an astrophysicist and lead author on a paper describing the findings. El-Badry goes on to explain that while there have been many other claimed detections of this nature, almost all have eventually been refuted. Gaia BH1 is the first "unambiguous detection of a Sun-like-star in a wide orbit around a stellar-mass black hole in our Galaxy."
The team did run into at least one dilemma, in that the system is not easily accommodated by standard binary evolution models. This leaves the team of astronomers asking how this binary system was formed, along with just how many of these dormant black holes exist.
El-Badry says he has been searching for dormant black holes for the last four years, using a wide array of data sets and methods. While his past findings have yielded more than a few binary systems that only appeared to be black holes, this is the first that has actually borne fruit.