Astronomers Find Three Planets in Habitable Zone of Gliese 667C, 22 Light-years Away

Posted on June 25, 2013

Three planets orbiting Gliese 667C

Astronomers have announced the discovery of three planets in the habitable zone of Gliese 667C. Three of these planets are confirmed to be super-Earths. This is the first time that three such planets have been spotted orbiting in this zone in the same system. It is also the first system found with a fully packed habitable zone. Gliese 667C is part of a triple star system known as Gliese 667. This star system is 22 light-years away in the constellation of Scorpius.

Previous studies of Gliese 667C had found that the star hosts three planets with one of them in the habitable zone. A team of astronomers led by Guillem Anglada-Escudé of the University of Göttingen, Germany and Mikko Tuomi of the University of Hertfordshire, UK, reexamined the system. They found evidence for up to seven planets around the star, with three of them in the habitable zone.

These planets orbit the third fainter star of the triple star system. Viewed from one of these newly found planets the two other suns would look like a pair of very bright stars visible in the daytime. At night they would provide as much illumination as the full Moon. The new planets completely fill up the habitable zone of Gliese 667C. The astronomers say there are no more stable orbits in which a planet could exist at the right distance to it.

Planets orbiting Gliese 667C

Mikko Tuomi (University of Hertfordshire) said in a statement, "We knew that the star had three planets from previous studies, so we wanted to see whether there were any more. By adding some new observations and revisiting existing data we were able to confirm these three and confidently reveal several more. Finding three low-mass planets in the star's habitable zone is very exciting."

Study co-author Rory Barnes (University of Washington) says, "The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star — instead of looking at ten stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them."

A copy of the research paper can be found here (PDF file).

Images: ESO/M. Kornmesser

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