Twin Stars Orbited By Three Giant Planets Discovered

Astronomers have discovered a trio of giant planets orbiting a pair of stellar 'twins' similar to our sun.

The twin stars - known as HD 133121A and HD 133131B - circle each other just 33.5 billion miles apart, a third of the distance of other binary systems.

Because of this, the three giant planets which they host are likely to have been scorched by their immense heat.

Astronomers also believe that one of the stars may have swallowed some smaller planets in the past.

HD 133121A has two planets - one about 1.5 times the size of Jupiter and another half the size of Jupiter.

Its twin hosts a third planet that is 2.5 times the mass of Jupiter. Finding such huge planets is extremely rare.

Dr Johanna Teske, an astronomer at the Carnegie Institution for Science in Washington DC, said: "We are trying to figure out if giant planets like Jupiter often have long and eccentric orbits.

"If this is the case, it would be an important clue to figuring out the process by which our Solar System formed, and might help us understand where habitable planets are likely to be found."

The stars were first spotted by the Planet Finder Spectrograph on the Magellan Clay Telescope at the Las Campanas Observatory in Chile.

They are relatively old stars, at about 9.5 billion years old, and are mainly composed of hydrogen and helium.

Details of the system are published in The Astronomical Journal, including the theory that one of the stars could have swallowed up some baby planets early in its life.