For the first time, astronomers with the NASA Kepler spacecraft mission have discovered a planet orbiting two stars. This is a fundamentally different kind of planetary system than has ever been discovered before. The new system is known as “Kepler-16” and consists of two stars — one about 69% the mass of the Sun, and the other only 20% the mass of the Sun, which circle each other every 41 days. Around both of these circles the Saturn-mass planet, half rock and half gas, known as Kepler-16b, with a period of 229 days.
via SETI Institute