Black holes are objects with high density and gravity. It swallows the surrounding stars and cannot escape the light. A research team at the European Southern Observatory, jointly operated by 14 European countries and Brazil, announced that they have discovered the closest black hole in the solar system, located just 1,000 light-years from Earth.
The research team had originally observed a binary star called HR6819, located in the place of a telescope, as part of a study on a binary star in which two stars orbit around the quantum center. It is said that HR6819 is a fifth star, and it is possible to see it with the naked eye from the Earth if the situation is in place.
Analysis of the orbit of a binary star revealed a strange orbit that appears to be dragged diagonally into the orbit of the binary star. The research team reportedly performed additional observations with the Lasilla Observatory Telescope (MPG/ESO 2.2-metre) operated in Chile. As a result, it was found that the HR6819 orbit does not mean that the two stars orbit around each other, but that three celestial bodies influence each other’s orbits. It was known that the third celestial body was at least four times the mass of the Sun, but no appearance was observed.
The researchers say that there can be no other invisible object with a mass of at least four times the sun’s except for a black hole. It means that the HR6819 is not a binary star as known before, but actually consists of three celestial bodies including a black hole.
The closest known black hole to the solar system was X-1 Monoceros, 3,300 light-years from Earth. But HR6819 is only 1,000 light-years away from Earth. The black hole discovered this time became the closest black hole to Earth. According to the research team’s analysis, the HR6819 black hole is at least 4.2 times the mass of the Sun and has the potential to be the smallest black hole found.
The reason why the HR6819 black hole has not been discovered so far is that the black hole itself has a small mass, does not absorb surrounding objects, and does not emit detectable X-rays. However, this discovery suggests that if a star with an unnatural orbit is found, an unknown black hole that is not actively active will be discovered.
The researchers say that there should be hundreds of millions of black holes in the galaxy, but we only know a small fraction of them. Knowing what to look for will give us a favorable position to find black holes. Studying the interaction of three stars, including black holes, is important for understanding the mechanisms by which black holes or neutron star collisions occur. It is also said that HR6819 may be an important hint for the LB-1, a massive stellar black hole that could not exist as it was discovered in 2019. He said he realized that LB-1 could be the same three stars as HR6819, and argued that it needed to make new observations based on the knowledge gained from the HR6819 black hole. Related information can be found here .