2015 RX245 is an extreme trans-Neptunian object, detached, on a highly eccentric orbit in the outermost region of the Solar System. It measures approximately 250 kilometers (160 miles) in diameter and is "possibly" a dwarf planet. It was first observed on 8 September 2015, by astronomers with Outer Solar System Origins Survey using the 3.6-meter Canada–France–Hawaii Telescope at Mauna Kea Observatories, Hawaii, in the United States.