Does having two Star Wars suns (or more) mean a planet will burn up?

Contributed by
Jun 8, 2018

Luke Skywalker may have seen many double sunsets on the desert planet of Tatooine, but would he even be alive long enough to blow up the Death Star if he lived on a planet orbiting two stars?

There are planets in galaxies far, far away that orbit two and even three stars. That may sound like a place you’d want to speed your X-wing out of if you wanted any chance of surviving an inevitable burst of fire. Even scientists were skeptical when Star Wars first landed in theaters. After analyzing more than 45,000 computer simulations that determined how long such alien worlds could remain in their orbits before gravity sent them crashing and burning (or flying randomly through the cosmos), they now believe otherwise.

"We ran the simulations for periods ranging from 1 million to 10 million years, in order to see if the systems are stable over very long periods," said Franco Busetti, of the University of the Witwatersrand in South Africa, at this month’s meeting of the American Astronomical Society. "The analysis shows that most configurations had large enough stable regions for planets to exist. Many of these areas are actually very habitable for planets."

Busetti recently co-authored a study, submitted to the journal Astronomy & Astrophysics, which could mean a seismic shift in how many planets we find with more than one star. There are many double-star systems believed to be in the Milky Way alone, but less than 40 known planets that experience a triple sunrise and triple sunset out of the 3,700 exoplanets currently known.

This isn't just the view from Tatooine. Credit: NASA

 This study could help astronomers figure out which multi-star systems should be included in a future survey and also how the observational searches for these systems should be conducted.

"The geometry of the stable zone indicates not only where to look for planets but how to look,” Busetti said.

KELT-4Ab is one of those worlds. It technically orbits one star—but—that star is orbited by an additional duo of stars, which are so close that Skywalker or anyone else standing on its surface would be seeing two glowing orbs about as bright as moonlight.

NASA’s Kepler space telescope has been unearthing most of those exoplanets, but is burning fuel much faster than any of them will be devoured by their stars, which is why the space agency launched TESS (Transiting Exoplanet Survey Satellite) to continue that mission. The ESA Gaia spacecraft, which maps stars, will also be instrumental in finding planetary systems orbiting more than one star.

Star Wars writers, take note for possible planet inspiration.