CAPE CANAVERAL, Fla. - A neighbor star has at least six planets in orbit, including three circling at the right distance for water to exist, a condition believed to be necessary for life, scientists said on Tuesday.

Previously, the star known as Gliese 667C was found to be hosting three planets, one of which was located in its so-called "habitable zone" where temperatures could support liquid surface water. That planet and two newly found sibling worlds are bigger than Earth, but smaller than Neptune.

"This is the first time that three such planets have been spotted orbiting in this zone in the same system," astronomer Paul Butler, with the Carnegie Institution in Washington, D.C., said in a statement.

Scientists say the discovery of three planets in a star's habitable zone raises the odds of finding Earth-like worlds where conditions might have been suitable for life to evolve.

"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 have a high chance of finding several of them," astronomer Rory Barnes, with the University of Washington, said in a statement.

Additional observations of Gliese 667C and a reanalysis of existing data showed it hosts at least six, and possibly, seven planets.

The star is located relatively close to Earth, just 22 light years (129 trillion miles/207 trillion km) away. It is about one-third the size of the sun and the faintest star of a triple star system.

In addition to the three well-positioned "super-Earths," two more planets may orbit on the fringe of the star's habitable zone and also could possibly support life.

The research will be published this week in the journal Astronomy & Astrophysics.