A team of astronomers has combinedNew observations of Gliese 667C with data from the HARPS instrument, installed in ESO’s 3.6-meter telescope in Chile, to reveal the existence ofa system with at least six planets. But what breaks all records is the fact thatthree of these planets are super-earths located in the area surrounding the starwithin whichthere could be liquid water, making them possible candidates for the presence of life.
Gliese 667C is a star widely studied by scientists. With only a third of the mass of the Sun, it is part of a triple star system known as Gliese 667, and is located 22 light years away, in the constellation of El Scorpio. Previous studies on Gliese 667C found that the star is home to three planets (eso0939, eso1214) and one of them is in the habitable zone. Now, a team of astronomers led by Guillem Anglada-Escudé, from the University of Göttingen (Germany), has reexamined the system by adding new observations carried out by the HARPS instrument and data obtained by other telescopes to the information that was already available. In this way they have discovered indications of the existence of more than seven planets around the star. These planets orbit the third weakest star in atriple star system. The other two suns would look like a pair of very bright stars visible during the day and, at night, they would provide illumination equivalent to that of the full Moon.
Observations have confirmed that three of those planets are super-earths – planets more massive than Earth, but less massive than planets like Uranus or Neptune – that lie within the habitable zone of their star, a limited zone around the star in which water can be present in liquid form if conditions permit.
“The number of potentially habitable planets in our galaxy is much higher than we might think when we consider that we can find several of them around each low-mass star – instead of searching for ten stars to find a single potentially habitable planet. We now know that we can search for just one star and find several planets ”, adds the co-author of the work Rory Barnes, from the University of Washington (USA).
