Planet found around Double Suns

This iconic scene from Star Wars may not be too far from reality.  It turns out that Kepler-16, has a planet orbiting around a binary star.  While the planet is much, much larger than the fictional Tatooine, about the size of Saturn, it illustrates that it is possible to have planets in stable orbits around a close binary star.

Why are orbits around binary stars thought to be unstable?  Much for the same reason that Jupiter acts like a giant scatterer in the outer Solar System.  Large bodies orbiting each other tend to push and pull orbits that come into their gravitational influence.  Actually NASA regularly uses this effect to change the orbits of satellites.  The larger the planet, or star, the larger the influence.  This can cause orbits to become unstable and if a close encounter occurs the body in question may be ejected in to interstellar space.  This is thought to be the cause of high velocity stars that we see flying through our galaxy.

However, in the case of Kepler-16 we have a close binary that also has a planet that is fairly close in, at only 0.7 AU.  Even more interesting is the fact that is has a low orbital inclination, meaning that the planet likely originally belonged to the star system when it formed.  Thus Kepler-16 likely shows that binary stars can have stable planets.

Not that this is entirely unexpected, theorists have been able to model stable orbits around binary stars for quite a while.  Observationally, though, this is the first time that a binary has been confirmed to have a planet.  Thus it should constrain the theoretical models of how planets form and orbit around binaries, giving us an even better chance of finding a planet in a similar situation to Tatooine.