A new rocky object similar to a comet and known as a minor planet has been discovered in the solar system some 3.2 billion km from Earth and could provide clues about the formation of comets, scientists have said.
The minor planet 2006 SQ372, which could be as wide as 96 km across, is slightly closer to the Earth than the planet Neptune and is orbiting the Sun in a 22,500-year, 241-billion-km trip, researchers from the Sloan Digital Sky Survey announced at a gathering of astronomers in Chicago.
Major planets, such as Earth and Mars, travel around the Sun in more circular orbits, but the object has a pronounced elliptical orbit similar to a comet, said Andrew Becker, the University of Washington astronomer who led the research.
The unusual orbit is similar to only one other known object, Sedna, a dwarf planet found in 2003.
The new minor planet could have come from the Oort Cloud, a distant reservoir of icy bodies that scientists believe is the birthplace of many asteroids, or may have formed "like Pluto, in the belt of icy debris beyond Neptune, then been kicked a large distance by a gravitational encounter with Neptune or Uranus", researcher Nathan Kaib said.
Minor planets is a broad category of objects in orbit around the Sun that are neither full-blown planets nor comets.
The category includes dwarf planets, like Pluto, whose downgrade from full planet sparked controversy in 2006.
The new planet is not being called a dwarf planet. Instead, scientists stressed its similarity to comets but noted it does not have the typical tail of debris that comets normally carry around with them.
Scientists happened upon the object while they were looking for supernova.
"If you can find things that explode, you can also find things that move," said Lynne Jones, an astronomer at the University of Washington, in a statement.