PARIS – Three “super-Earth” planets have been found orbiting a nearby star at a distance where life could exist in theory, according to a record-breaking tally announced by the European Southern Observatory.
The three are part of a cluster of as many as seven planets that circle Gliese 667C, one of three stars located a relatively close 22 light-years from Earth in the constellation of Scorpio.
The planets orbit Gliese 667C in the “Goldilocks zone” — a distance from the star at which the temperature is just right for water to exist in liquid form rather than being stripped away by stellar radiation or locked permanently in ice.
“It’s exciting that we’ve found a nearby star that has so many planets in its habitable zone,” said University of Washington astronomer Rory Barnes, who was part of the team.
The planets are called super-Earths because they are bigger than Earth but similar in being rocky planets rather than gas giants like Jupiter.
It is the first time that so many super-Earths have been netted in one scientific haul, and shows the value of seeking out low-mass, sunlike stars that appear to generate these promising worlds, the astronomers said. Still unconfirmed is whether the trio are rocky planets, as opposed to gassy worlds where toxic or suffocating gases would make life impossible.
“These planets are good candidates to have a solid surface and maybe an atmosphere like the Earth’s, not something like Jupiter’s,” Barnes said. He said their proximity makes it likely they are tidally locked, so the same hemisphere always faces the star. “Fortunately, we know that this state can still support life,” Barnes said.