An international team of astronomers spotted the tiny world using the Canada-France-Hawaii Telescope as part of the ongoing Outer Solar System Origins Survey.
“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,” Michele Bannister of the University of Victoria in British Columbia said in a statement
“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.”
Planet RR245 is around 435 miles wide, just over 5% the width of the Earth, and has one of the largest orbits of any dwarf planet, taking an estimated 700 years to travel around the sun.
There are believed to be as many as 200 dwarf planets in the Kuiper Belt
, the huge mass of comets, frozen rocks and other objects orbiting the sun beyond Neptune.
However, only five objects — Ceres, Pluto
, Haumea, Makemake
, and Eris — had previously been observed well enough to be sure they fit the classification for dwarf planet (and weren’t, say, mere planetoids, or moons of other trans-Neptunian objects).
“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,” says
“The size of RR245 is not yet exactly known, as its surface properties need further measurement. It’s either small and shiny, or large and dull.”