The largest planet yet discovered around a double-star system was detected by a team of astronomers from NASA’s Goddard Space Flight Center using the Kepler Space Telescope to identify the new planet, Kepler-1647b.
Planets that orbit two stars are known as circumbinary planets, or sometimes “Tatooine” planets, after Luke Skywalker’s home world in “Star Wars.” Using Kepler data, astronomers search for slight dips in brightness that hint a planet might be passing or transiting in front of a star, blocking a tiny amount 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 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.
“But finding circumbinary planets is much harder than finding planets around single stars,” said San Diego State University (SDSU) astronomer William Welsh, one of the paper’s coauthors. “The transits are not regularly spaced in time and they can vary in duration and even depth.