Astronomers discover new 'dwarf planet' beyond Pluto

Researchers say '2015 RR245' takes 700 years to orbit the sun

Astronomers discover new 'dwarf planet' beyond Pluto

Image: RR245 orbit. Alex Parker, OSSOS

Astronomers say they have newly discovered a 'dwarf planet' in our solar system, far beyond Pluto.

'2015 RR245' - which will be properly named once more is known about it - takes 700 years to orbit the sun, and is said to be more than 120 times further from the sun than Earth.

In contrast, Pluto - which itself was reclassified as a dwarf planet - takes 248 years to complete its orbit.

The new planet was found by an international team of astronomers, including ones from the University of Victoria in Canada.

Michele Bannister, who is conducting postdoctoral research at the university, said: “The icy worlds beyond Neptune trace how the giant planets formed and then moved out from the sun. They let us piece together the history of our solar system.

“Worlds of this size are fascinating because they can potentially tell us about what makes an object go from being an unchanging lumpy mashed-together structure of ice and rock to having geological processes that separate and rearrange its material, as happens on Pluto,” she added.

NASA says there are currently five officially recognised dwarf planets in our solar system: Ceres, Pluto, Eris, Makemake and Haumea.

There are estimated to be dozens more, but only a few are large enough or bright enough to be studied.

Ms Bannister says it is "really exciting" to discover another dwarf planet that can be observed in detail, as "almost all of these icy worlds are painfully small and faint".