TOKYO — Scientists concluded in 2006 that Pluto is too small to be defined as a planet, but a research group at Japan's Kobe University said Wednesday that their research indicates the possible existence of another solar system planet beyond Neptune.
The unidentified planet is likely to meet the definition of a planet in the solar system set by the International Astronomical Union in 2006, according to Tadashi Mukai, a professor at Kobe University's Graduate School of Science.
"We might well find it within a decade if we launch a large-scale study," said Mukai.
According to the research conducted by Mukai and Patryk Lykawka, the planet is about 30-70 percent of Earth's mass and located more than 12 billion kilometers from Earth.
It apparently tilts about 20-40 degrees to the plane of orbit and circles the sun in an elliptical orbit every thousand years.
In August 2006, the IAU made a historic decision to redefine the solar system as consisting of eight planets, excluding Pluto from what had long been thought a nine-planet system.
(Original headline: Another planet may be beyond Neptune: researchers )
