US astronomers have found new evidence for the existence of a hypothetical ninth planet in the solar system. They confirmed that clustering of the Kuiper Belt objects' orbits is not a result of observation bias and may indeed be caused by a massive object or planet X that has not yet been discovered. This is reported in an article published in the arXiv preprint repository.
The authors of the new paper took into account the possibility of biased data, but even so, orbit clustering is statistically unusual. The probability that it is a consequence of chance is only 0.4 percent. It also allowed researchers to pinpoint the location of the ninth planet's likely orbit. It turned out that it should be slightly closer to the Sun than originally assumed. And if the planet exists, it should be discovered by the Vera Rubin Observatory, which will be operational in 2022.
Back in 2016, American astronomers Michael Brown and Konstantin Batygin studied the statistical distribution of the orbits of Kuiper belt objects and came to the conclusion that clustering must be caused by an outer planet that has not yet been discovered. According to their calculations, this object has a mass of five Earths and about ten times more distant from the Sun than Neptune.