Astronomers studying Gliese 667C, a nearby star in the constellation Scorpius, have expanded on previous observations to find that it has at least 6 planets, with three of them in the habitable zone. These three are all super-Earths, meaning that they’re rocky planets that are several times the size of Earth.

 The habitable zone around a star is the distance at which the range of possible temperatures allows for a planet to have liquid water, although this does not guarantee that the planet will be a home to living organisms or even that it has any water.
 Previous studies of Gliese 667C has found three planets, with one in the habitable zone. The more recently discovered extra planets were found by a team of astronomers led by Guillem Anglada-Escudé of the University of Göttingen, Germany and Mikko Tuomi of the University of Hertfordshire using data collected by HARPS (the High Accuracy Radial velocity Planet Searcher, a 3.6 meter telescope in Chile), the ESO’s Very Large Telescope, the W.M. Keck Observatory and the Magellan Telescopes. By applying a mathematical reduction to the slight variations in the star’s radial velocity, they found six planets, as well as a possible seventh. The three super-Earth’s completely fill the star’s habitable zone, meaning that any extra planets in the zone would have unstable orbits and soon be ejected. This is the first time such a configuration has been found.
 Gliese 667C is a small star, just one third of the mass of the Sun, giving it a habitable zone that is much larger than that in our own Solar System (which extends from just beyond the orbit of Venus to just before Mars) but which lies very close to the star. It is the smallest member of a widely distributed triple-star system. Viewed from one of the planets, the other two suns of the system would appear as very bright stars, visible in the day and as bright as the full moon at night.
 Astronomers studying exoplanets have been excited by this find, since it shows that they they have many more worlds to study than they might have hoped for – rather than searching ten stars to find a single exoplanet, they’ve found six around a single star!