Planets orbiting a binary star system — like Tatooine, the fictional home planet of Luke Skywalker in Star Wars — could form with surprising ease.

Most known circumbinary planets orbit close to their stars, where the competing gravitational forces from the two stars make the orbits of nearby objects unstable or intersect. This prevents debris from clumping together to form planets. But Benjamin Bromley of the University of Utah in Salt Lake City and Scott Kenyon of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, show with simulations that a zone exists near the host stars where the orbits of debris wobble, but do not cross, allowing for planet formation.

This suggests that Earth-sized 'Tatooines' could be common and that more are likely to be discovered soon.

Astrophys. J. 806, 98 (2015)