Spotted: A faraway Uranus-like planet

Astronomers have discovered a planet 25,000 light years away that resembles Uranus of our solar system.

The discovery may help astronomers solve the mystery surrounding the origins of the ice giants in our solar system.

While Uranus and Neptune are mostly composed of hydrogen and helium, they both contain significant amounts of methane ice, which gives them their bluish appearance.

Though astronomers are not sure about the composition of the new planet, the distance from its star suggests that it is an ice giant and its orbit resembles that of Uranus

"Nobody knows for sure why Uranus and Neptune are located on the outskirts of our solar system, when our models suggest that they should have formed closer to the sun," said Andrew Gould, professor of astronomy at the Ohio State University in the US.

The new planet orbits one star in a binary star system, with the other star close enough to disturb the planet's orbit, found the team.

Astronomers spotted the new solar system due to a phenomenon called gravitational microlensing - when the gravity of a star focuses the light from a more distant star and magnifies it like a lens.

The team observed two separate microlensing events, one in 2008 that revealed the main star and suggested the presence of the planet, and one in 2010 that confirmed the presence of the planet and revealed the second star.

Both observations were done with the 1.3 metre Warsaw Telescope at the Las Campanas Observatory in Chile as part of the Optical Gravitational Lensing Experiment (OGLE).

"Only microlensing can detect these cold ice giants that, like Uranus and Neptune, are far away from their host stars. This discovery demonstrates that microlensing is capable of discovering planets in very wide orbits," concluded Radek Poleski from the Ohio State University.

The study appeared in The Astrophysical Journal.