https://phys.org/news/2024-04-evidence-planet.html
by Bob Yirka , Phys.org
A small team of planetary scientists from the California Institute of Technology, Université Côte d'Azur and Southwest Research Institute reports possible new evidence of Planet 9. They have published their paper on the arXiv preprint server, and it has been accepted for publication in The Astrophysical Journal Letters.
In 2015, a pair of astronomers at Caltech found several objects bunched together beyond Neptune's orbit, near the edge of the solar system. The bunching, they theorized, was due to the pull of gravity from an unknown planet—one that later came to be called Planet 9.