University of Victoria researchers and their collaborators on an international research team have discovered a new dwarf planet.
The dwarf planet, about one and a half times the size of Vancouver Island, orbits in small icy worlds beyond Neptune that trace how giant planets formed and moved out from the sun, said astronomer Michele Bannister.
“They let us piece together the history of our solar system,” said Bannister, who is doing post-doctoral research at UVic.
“Almost all of these worlds are painfully small and faint, so it’s really exciting to find one that’s large and bright enough to study in detail.”
The planet, temporarily designated 2015 RR245 by the International Astronomical Union’s Minor Planet Center, was found using the Canada-France-Hawaii Telescope on Maunakea, Hawaii. The dwarf planet is estimated to be 700 kilometres in diameter and lies within the Kuiper Belt, several billion kilometres away from Earth.
JJ Kavelaars, an adjunct professor at UVic and a researcher with the National Research Council’s Herzberg Astronomy and Astrophysics in Victoria, first sighted the planet in February, in images from September 2015.
The tiny dot of light moved so slow on their screen that researchers realized it had to be at least twice as far as Neptune from the sun, Bannister said.
The team became more excited after realizing that the object’s orbit takes it more than 120 times farther from the sun than Earth.
“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 said.
Since RR245 has been observed for only one of the 700 years it takes to orbit the sun, other details such as its origins and how its orbit will evolve in the far future remain unknown.
RR245 is one of the few dwarf planets — a category that also includes Pluto and Eris — that has survived to the present day. The vast majority were destroyed or thrown from the solar system in the chaos that ensued as the giant planets moved to their present positions.
