Researchers have located a new system with at least six planets, of which a record-breaking half fall into the category of super-Earths - planets more massive than Earth but less massive than planets like Uranus or Neptune - in the zone around the star where liquid water could exist, making them likely candidates for life.

The first known system with a fully packed habitable zone, the discovery was made by a team of scientists who combined new observations of the star Gliese 667C with existing data from HARPS at the European Southern Observatory's 3.6-meter telescope in Chile.

Gliese 667C is a well-studied star with just over one-third of the mass of the Sun. Part of a triple star system, it's located a mere 22 light-years away in the constellation Scorpius.

Previous studies of the star found that it hosts three planets, with one in the habitable zone. However, a team of astronomers led by Guillem Anglada-Escude of the University of Gottingen, Germany and Mikko Tuomi of the University of Hertfordshire, the United Kingdom, decided to reexamine the system.

In so doing, they added new HARPS observations, along with data from ESO's Very Large Telescope, the W.M. Keck Observatory and the Magellan Telescopes to the already existing picture.

In all, the researchers found evidence for as many as seven planets orbiting the Gliese 667C with no possibility of further planets located in the habitable zone, according to the researchers.

Of the discovery, Tuomi explained the researchers were curious to know if there could possibly be more planets circling the star than the three scientists had already spotted. None of them, however, ever expected to be as lucky as they were.

"Finding three low-mass planets in the star's habitable zone is very exciting!" Tuomi said of the discovery without precedence.

The find, according to co-author Rory Barnes of the University of Washington, could change the very way astronomers look for other Earth-like planets.

"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," he said.

Compact systems around Sun-like stars are abundant within the Milky Way, and while this means that planets orbiting close to them are hot and poorly-construed for life, this is not the case for dimmer stars, such as Gliese 667C. In this case, the habitable zone lies entirely within an orbit the size of Mercury's, much closer in than for the Sun.

Another major takeaway, according to the scientists, has less to do with stars and potential life and more with the search itself.

"These new results highlight how valuable it can be to re-analyse data in this way and combine results from different teams on different telescopes," Anglada-Escudé concluded.