Note: This is a press release from San Diego State University.
If you cast your eyes toward the constellation Cygnus the Swan, you’ll be looking in the direction of the largest planet yet discovered around a double-star system. It’s too faint to see with the naked eye, but a team led by astronomers from NASA’s Goddard Space Flight Center and San Diego State University used the Kepler Space Telescope to identify the new planet, Kepler-1647b.
Planets that orbit two stars are called circumbinary planets, or “Tatooine” planets, after Luke Skywalker’s homeland in “Star Wars.” To detect planets, the Kepler telescope looks for slight dips in brightness that hint a planet might be transiting in front of a star, blocking some of the star’s light.
Kepler-1647b is 3,700 light-years away and approximately 4.4 billion years old, roughly the same age as the Earth. The stars are similar to the Sun, with one slightly larger than our home star and the other slightly smaller. The planet has a mass and radius nearly identical to that of Jupiter, making it the largest transiting circumbinary planet ever found.
“It looks like more than 40% of circumbinary planets are in the habitable zones of their stars,” said Laurance Doyle, a coauthor on the paper and astronomer at the Carl Sagan Center, SETI Institute. “It seems that the scene from Star Wars where Luke Skywalker is watching the double sunset may not be so rare after all. But physics might be more difficult—everything from shadows to rainbows would come in pairs!”