A so-called Super-Earth located 42 light years away from us has been identified, with scientists claiming it occupies a privileged orbit conducive to liquid water and, if conditions are correct, even life. The planet, at least seven times the size of the Earth, is part of a six planet system orbiting the HD 40307 star in the constellation Pictor, Discovery reports, though is the only one of the sextet to be in the "habitable zone" where water could remain liquid rather than as gas or ice.
HD 40307 and its six planets was first discovered in 2008; the star itself is around three-quarters of the size of our sun, and the Super-Earth occupies the outermost orbit. It's possible that further planets orbit the same sun, but the difficult positioning of the cluster makes observing it accurately from Earth difficult.
In fact, no follow-up research to the initial 2008 identification is currently on the roadmap. That was done initially by the La Silla Observatory's High Accuracy Radial velocity Planet Searcher (HARPS) which can track gravitational impact from large bodies on the light from stars they orbit.
The Super-Earth was almost missed, researchers Mikko Tuomi from the University of Hertfordshire and Guillem Anglada-Escude, from the University of Goettingen say, because the further out from the star, the harder it is to differentiate between typical solar activity and what is real gravitational effect.
Of course, water in itself isn't enough to ensure life develops on a planet. Other research recently published suggested that the presence of an asteroid belt in a certain position in a system could be essential for life to be sparked, potentially dramatically reducing the number of prospective planets which could have developed alien life.
The Super-Earth may not even be rocky, astronomers involved admit, with insufficient data to ascertain what materials it is made up of. It has an orbit of one rotation around HD 40307 every 320 days.
[Image credit: J. Pinfield, for the RoPACS network at the University of Hertfordshire]