European and U.S. astronomers say new data on a well-studied star suggests it has at least six planets, three of them possible candidates for life.

New observations of the star Gliese 667C show three of its planets are super-Earths lying in the zone around the star where liquid water could exist, the European Southern Observatory reported Tuesday from its headquarters in Germany.

"We knew that the star had three planets from previous studies, so we wanted to see whether there were any more," Mikko Tuomi of the University of Hertfordshire in England said. "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!"

This is the first time that three such planets have been spotted orbiting in this zone in the same system, astronomers said.

"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 10 stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them," study co-author Rory Barnes of the University of Washington said.