Astrophys. J. (in the press); preprint at http://arxiv.org/abs/1409.1249 (2014)

Around half of the stars in the sky are thought to come in pairs — orbiting around one another. But what of stars with exoplanets? Are binary stars just as likely to play host to planets as those that go it alone? The answer is yes, according to a survey of exoplanet host stars undertaken by Elliott Horch and co-workers.

The team used speckle imaging to observe more than 600 Kepler Objects of Interest, picking up nearly 50 probable pairs. Their model suggests that this indicates that 40–50% of the stars with exoplanets may be binaries. However, the study can't yet determine which star is the one being orbited. And the Kepler space telescope has even found exoplanets that orbit star pairs sitting very close together.

The idea that a planet like ours might boast a pair of Suns is an appealing kind of science fiction — an inspiration to countless films and comic books. And for such a planet, night might be its own science fiction.