Astronomers spot most distant object in solar system

WASHINGTON (AFP) - Astronomers have discovered a mysterious dwarf planet that is three times farther away than Pluto and believed to be the most distant object in our solar system.

The discovery of the dwarf planet known as V774104 was announced Tuesday at a meeting of the American Astronomical Society near the US capital and could indicate the presence of more rogue planets in our celestial neighbourhood.

The dwarf planet currently sits 15.4 billion km from the Sun.

It is believed to be between 500km and 1,000km across.

Scott Sheppard, an astronomer at the Carnegie Institution for Science in Washington, announced the discovery and said its orbit remains unknown, for now.

"It could end up joining an emerging class of extreme solar system objects whose strange orbits point to the hypothetical influence of rogue planets or nearby stars," said a report in the journal Science.

The discovery was made using Japan's 8m Subaru Telescope in Hawaii.

The dwarf planet lies at a distance of about 103 astronomical units (AU) away from the Sun. One AU is the distance between Earth and the Sun.

Previously, the most distant solar system object was announced in 2005 - a dwarf planet named Eris that was 97 AU from the Sun.

"The discovery of V774104 is more proof that the solar system is bigger than we thought," said Joseph Burns, professor of engineering and astronomy at Cornell University.

"We need a little more time to pin down the orbit and determine the object's exact size, but it must be big to see it at this distance."