First Exoplanet Discovered Orbiting Two Stars

astroengine writes "For the first time, astronomers have discovered an exoplanet orbiting binary stars. Kepler-16b, a Saturn-sized world approximately 200 light-years away, orbits Kepler-16, two stars locked in a mutual dance. Although other exoplanets are known to exist in binary systems, they have only been known to be orbiting one star of the binary pair; Kepler-16b orbits both. No doubt Kepler-16b will excite memories of Tatooine, Luke Skywalker's homeworld, but the double sunset is where the similarities end. Kepler-16b would be anything but a desert world; it is the approximate size of Saturn, it is extremely cold, and its average density is that of water."

Re:Deserts can be cold

[MightyMartian]

It's Saturn sized with density of water. It's a friggin' gas giant. It has no surface, unless you count the super-dense core that's probably hydrogen in a metallic state.

Re:Density?

[cnettel]

Kepler is observing the dimming of the light of the star (basically a part of the star disc is shadowed by the planet), when the planet transits directly in the line of sight between Kepler/Earth and the star. Hence, you can get a cross-section area, and by assuming the planet to be reasonably spherical (a fair assumption), you get the volume.