By Nadia Drake
MOUNTAIN VIEW, Calif. — One of the many worlds circling faraway suns is tracing a most Earthlike path: The planet Kepler-22b has a 290-day orbit that parks it firmly within its star’s life-friendly zone, scientists announced December 5 at the first Kepler Science Conference.
With a radius 2.4 times larger than Earth’s, Kepler-22b is the smallest planet confirmed to sit comfortably in a sunlike star’s “habitable zone,” or the zone around a star where temperatures allow liquid water to exist. Kepler-22b’s home star — shining 600 light-years away near the constellation Cygnus — is very similar to the sun, though a bit cooler.
“Today’s discovery is a tantalizing indication that with time, Kepler might find true Earth analogs, if they exist,” said Pete Worden, the director of NASA’s Ames Research Center in Mountain View, Calif. The Kepler team’s goal is to detect Earth-sized exoplanets within the habitable zones of their parent stars, a task that requires years of observing time.