We report the detection of Kepler-47, a system consisting of two planets
orbiting around an eclipsing pair of stars. The inner and outer planets have
radii 3.0 and 4.6 times that of the Earth, respectively. The binary star
consists of a Sun-like star and a companion roughly one-third its size,
orbiting each other every 7.45 days. With an orbital period of 49.5 days,
eighteen transits of the inner planet have been observed, allowing a detailed
characterization of its orbit and those of the stars. The outer planet's
orbital period is 303.2 days, and although the planet is not Earth-like, it
resides within the classical "habitable zone", where liquid water could exist
on an Earth-like planet. With its two known planets, Kepler-47 establishes that
close binary stars can host complete planetary systems.Comment: To appear on Science Express August 28, 11 pages, 3 figures, one
table (main text), 56 pages, 28 figures, 10 table
