Scientists have identified three super-Earth in what is the first "fully packed habitable zone" ever discovered.
The research team found three planets orbiting a star which can be seen in the Scorpius (scorpion) constellation, and each are candidates for hosting extraterrestrial life, according to a University of Göttingen press release.
A habitable zone is an area that could hold water, based on its relation to a star.
The star, Gliese 667C which is about 22 light-years away has been well-studied. It's relatively close to Earth, much closer than other suspected life-hosting planets.
Super-Earths are more massive than the Earth itself, but smaller than planets like Uranus and Neptune.
"We knew that the star had three planets from previous studies, so we wanted to see whether there were any more," said Mikko Tuomi of the University of Hertfordshire, who participated in the study. "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!"
The planets orbit the faintest star in a three-star system. The researchers speculated the two other stars would be visible during both day and night from the surface of the planets, and most likely give off light equivalent to a full moon.
Planet systems that orbit stars have been found in the Milky Way before, but they were always too close to the star in question and too hot to host life.
These newly discovered planets orbit closer to Gliese 667C than Earth orbits the sun, they are about as far away as Mercury, but the star is much weaker.
"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 have a high chance of finding several of them," said co-author Rory Barnes of the University of Washington.
The stars were discovered using HARPS data from the European Southern Observatory (ESO), a 3.6 meter telescope located in Chile.
"These new results highlight how valuable it can be to re-analyze data in this way and combine results from different teams on different telescopes," said Anglada-Escudé, who led the study.
