Newly discovered super-Earth is one of the best candidates for life yet

European astronomers using the HARPS planet searcher have detected a super-Earth orbiting an orange dwarf star that's only 44 light years away. The researchers aren't entirely sure if it's a rocky planet or not, but it does have a number of key features that make it an excellent candidate for life, including its presence within the solar system's habitable zone — and a spin that allows for day and night cycles.

The discovery was made by Mikko Tuomi of the University of Hertfordshire in the UK, and Guillem Anglada-Escude from Germany's University of Goettingen. Their paper is set to be published in an upcoming issue of the journal Astronomy & Astrophysics.

The planet, called HD 40307g, is about 7 times the mass of Earth and orbits its sun along with five other planets (all of which are too close to their parent star to make them viable candidates for life). It's not clear if the planet is terrestrial — but if it is, it may have the right conditions for habitability.

For one, it is situated within the solar system's Goldilocks zone; the planet features a very reasonable year that is 320 Earth days in length. Consequently, the planet receives a similar amount of solar energy compared to Earth (it gets about 62% of the radiation that Earth gets from the sun). This unto itself is big news as most super-Earths that have been discovered tend to be situated far too close to their parent stars.

And excitingly, HD 40307g is the closest planet to the Earth within a habitable zone that doesn't have a tidally locked orbit — a feature that gives the planet a night and day cycle. While this may not be a prerequisite for life, our example here on Earth shows that in may be a crucial ingredient — what prevents one side of the planet from getting constant exposure to the sun. It may also provide cyclical rhythms that induce geological bio-friendliness.

As noted, the astronomers aren't sure about the planet's composition. But they point out that other observations of nearby hot super-Earths show that a good fraction of the planets in that general cosmological neighborhood are made from rock. Clearly, their future observations should focus on finding out for sure.

Sources: Reuters, Discovery.

Image: J. Pinfield, for the RoPACS network at the University of Hertfordshire.