Scientists using a telescope in Hawaii have discovered a never-before-seen dwarf planet lurking within the ring of icy bodies on an eccentric orbit far beyond Neptune. The small new world — temporarily named 2015 RR245 — is about 435 miles in diameter and is in a wide orbit that takes it farther away from the sun than even Neptune. The newly spotted dwarf planet joins a cohort of other small worlds in that part of space, including Pluto. Together, dwarf planets can help scientists learn a lot about how the solar system became what we see today.
They let us piece together the history of our solar system. But almost all of these icy worlds are painfully small and faint: It’s really exciting to find one that’s large and bright enough that we can study it in detail.
Michele Bannister, one of the researchers who helped discover the dwarf planet using the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii
They are smaller than ordinary planets, and they orbit the sun at a much greater distance, traveling in a zone littered with other objects like asteroids. There are thought to be dozens of them in our solar system, but only a handful have been identified so far. They include Eris and Ceres, as well as Pluto, which was downgraded to a dwarf planet in a 2006 decision that remains contested to this day. The discoverers of RR245 now have the right to propose a name for their find.