Scientists have found a potential super-Earth, the best candidate yet to harbor water, and possibly even life, located in the habitable zone of its host star, with more habitable exoplanets expected to be found.

The planet, called GJ 667Cc, is estimated to be at least 4.5 times as massive as Earth, which makes it a so-called super-Earth. According it researchers, it takes roughly 28 days to make one orbital lap around its parent star, which is located a mere 22 light-years away from Earth, in the constellation Scorpius.

According to the study, which was led by Guillem Anglada-Escudé and Paul Butler of the Carnegie Institution for Science, a private, nonprofit research organization based in Washington, D.C., the discovery of a planet around GJ 667C, the host star, came as a surprise to the astronomers, because the entire star system has a different chemical makeup than our sun.

The fortuitous discovery could mean that potentially habitable alien worlds could exist in a greater variety of environments than was previously thought possible, the researchers said. What scientists call the habitable zone of a star depends on whether liquid water can survive on a planet's surface, since it is accepted that life exists virtually wherever there is liquid water on Earth.

"It's the Holy Grail of exoplanet research to find a planet around a star orbiting at the right distance so it's not too close where it would lose all its water and boil away, and not too far where it would all freeze," said Steven Vogt, an astronomer at the University of California, Santa Cruz, one of the authors of the study.

"This planet is the new best candidate to support liquid water and, perhaps, life as we know it," said Anglada-Escudé.

The researchers used public data from the European Southern Observatory combined with observations from the W.M. Keck Observatory in Hawaii and the new Carnegie Planet Finder Spectrograph at the Magellan II Telescope in Chile in making their discovery.

"Statistics tell us we shouldn't have found something this quickly this soon unless there's a lot of them out there," Vogt said. "This tells us there must be an awful lot of these planets out there. It was almost too easy to find, and it happened too quickly."

With the GJ 667C system being relatively nearby, Vogt said that it also opens exciting possibilities for probing potentially habitable alien worlds in the future, which cannot be done easily with the planets that are being found by NASA's prolific Kepler spacecraft since these planets coming are typically thousands of light-years away

Initial observations also suggest that more planets could exist in this system, including a gas giant planet and another super-Earth that takes about 75 days to circle the star.

However, more research will be needed to confirm these planetary candidates, as well as to glean additional details about the potentially habitable super-Earth, the scientists said in their study which will be published in the Astrophysical Journal Letters.