Kepler-1647b: NASA Astronomers Just Discovered a Huge "Tatooine Planet" With 2 Suns

NASA

NASA's Goddard Space Flight Center just discovered a planet the size of Jupiter orbiting two stars. It's called Kepler-1647b.

Planets that orbit two stars are appropriately nicknamed "Tatooine planets," after Luke Skywalker's home planet in Star Wars with two suns.

Luke Skywalker walks toward the double sunset in Star Wars: A New Hope.  YouTube

Kepler-1647b is the largest Tatooine planet discovered so far. Here's how its size compares to other exoplanets that orbit two stars:

Kepler-1647 b is the largest circumbinary planet discovered yet.  Lynette Cook/NASA

One of its stars is slightly larger than our sun; one is slightly smaller. The whole planet system sits about 3,700 light-years away from Earth. 

Kepler-1647b wasn't easy to find using the transit method exoplanet-hunting astronomers rely on. Usually they can spot exoplanets when they pass in front of a star and cause a dip in the star's brightness. 

"But finding circumbinary planets is much harder than finding planets around single stars," San Diego State University astronomer William Welsh, co-author on the new research paper, said in a statement. "The transits are not regularly spaced in time and they can vary in duration and even depth."

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It takes about 1,107 days for the planet to orbit its pair of stars, which puts it inside the habitable zone. That means it orbits at a distance from the stars where it could potentially hold liquid water on its surface. However, the planet is a gas giant like Jupiter, which makes it unlikely to host life, according to NASA.

Even though we probably won't find aliens (or Luke) there, astronomers are still excited by this find. 

"Habitability aside, Kepler-1647b is important because it is the tip of the iceberg of a theoretically predicted population of large, long-period circumbinary planets," Welsh said in the statement.

The research will be published in the Astrophysical Journal.