A possible Earth twin has been confirmed orbiting a sunlike star 600 light-years away—and the new planet may be in just the right spot for supporting life, NASA announced Monday.

Discovered by the Kepler space mission, the new planet—dubbed Kepler-22b—is the first world smaller than Neptune to be found in middle of its star’s habitable zone.

Also called the Goldilocks zone, the habitable zone is the region around a star where a planet’s surface is not too hot and not too cold for liquid water—and thus life as we know it—to exist.

(Also see “New Planet May Be Among Most Earthlike—Weather Permitting.”)

Other planets have been spotted in the habitable zones of their stars, but most of those worlds are Jupiter- or Neptune-size bodies that are unlikely to harbor life.

“The number of confirmed sub-Neptunian worlds in their habitable zones are few and far between, because they are the hardest ones to find,” said Natalie Batalha, Kepler’s deputy science team leader at San Jose State University in California.

(Related: “Six New Planets—Mini-Neptunes Found Around Sunlike Star.”)

In fact, only two known planets fit this description so far—Gliese 581d and HD 85512—and both worlds orbit at the very edges of their stars’ habitable zones, making them more akin to Venus and Mars than to Earth.

“What makes this particular discovery so exciting is that this planet is right smack in the middle of the habitable zone,” Batalha said.

“It’s also orbiting a star that’s almost a twin of our sun, whereas the other two detections are orbiting significantly cooler stars.”