Why the Binary Star Planet Matters.

So, if you hadn't noticed it's raining planets. There are so many discoveries coming so fast that it is hard for anyone - astronomers like myself included - to keep up. Ideas that seemed wild a few years ago are now being shown to be an inescapable fact. This is science at its best, tossing our preconcieved ideas out the window to show us that nature is far more imaginative than we are.

One of the most significant finds in recent years has been the understanding that planets can exist in stable orbits around binary stars. Now we add the much-heralded discovery of Kepler-16 A to the binary star planet inventory. Kepler-16 A is a planet that appears to orbit both stars at once, rather than being gravitationally locked to just one of the sun's as that star dances around its partner.

So why is this important (other than letting us trot out that image of Luke Skywalker staring into the double setting suns of Tatooine?) The answer is simple.

About half of the stars in the galaxy come with siblings. Single stars like our sun make up the other half. Some of these binary stars live on tight orbits, and some are so widely separated they hardly feel each other's presence. Either way binary stars are an important component of the galactic ecology. That makes their ability to host planets a crucial question. Now we know that, yes, binary stars can hold on to planets in a variety of orbits.

So here comes the next question. Can binary star planets ever be home to life?

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