Can a planet orbit more than one star?

A planet can certainly orbit more than one star, just like the planet Tatooine in Star Wars. Thanks to Kepler and the Transiting Exoplanet Survey Satellite (TESS), we have discovered around a dozen circumbinary planets – those orbiting around binary stars – which we sometimes call Tatooines. The orbits of these planets encircle the central binary far enough away for the whole system to be dynamically stable. We also know of planets which orbit within stellar binaries; such planets orbit around one of the stars, with the other star moving on a wider orbit. And two stars is not a limit. For example, our closest stellar neighbour, Proxima Centauri, is part of a loosely bound triple system and is known to be host to at least one planet. Also, very recently it was proposed – albeit based on indirect evidence – that a young stellar triple system, GW Orionis, may be orbited by a massive planet in a circumtriple configuration. Planets are not averse to residing in crowded stellar systems.

Professor Roman Rafikov, Department of Applied Mathematics and Theoretical Physics, University of Cambridge