"Because of the very cold temperature, its surface would be covered with ice, icy ammonia and methane," Kobe University professor Tadashi Mukai, the lead researcher, told AFP.
The study by Mukai and researcher Patryk Lykawka will be published in the April issue of the US-based Astronomical Journal.
"The possibility is high that a yet unknown, planet-class celestial body, measuring 30 percent to 70 percent of the Earth's mass, exists in the outer edges of the solar system," said a summary of the research released by Kobe University.
Sunday, March 02, 2008
Japanese scientists eye new planet