Astronomers at the Keck telescope at Mauna Kea, Hawaii, have confirmed the discovery of an unusual planet, about 5000 light-years away from Earth. The gas giant, slightly larger than Neptune, orbits a pair of Sun-like stars, which are then orbited by a second pair of stars – the first confirmed four-star planetary system

The planet has caused a stir amongst academics and astronomers, who are trying to find out why its orbit remains stable despite being pulled by the gravity of four stars. It was discovered by Kian Jek of San Francisco and Robert Gagliano of Cottonwood, Arizona – two volunteers using the Planethunters.org website.

Planet Hunters was set up in 2010 and publishes a vast amount of data gathered by the Kepler Space Telescope. Volunteers are asked to look for dips in light caused by planetary orbits, and so far, more than 170,000 members of the public have participated in the project. As this is the first time that the website’s users have had a planetary discovery confirmed by professional astronomers, the distant world has been named PH1 – short for Planet Hunters 1.