Outer Space

Astronomers Discover The Largest Known Planet That Orbits Two Suns

There's a famous scene near the beginning of Star Wars IV: A New Hope where Luke Skywalker is gazing introspectively at Tatooine's two suns setting over the horizon. Tatooine is an (albeit fictional) example of a circumbinary planet—one that orbits not one, but two stars. In June 2016, astronomers announced they had discovered the largest ever circumbinary planet. Its name? Kepler-1647b.

Related: Some Of The Strangest Exoplanets In Space

This comparison of the relative sizes of several Kepler circumbinary planets shows how much larger Kepler-1647 b is than the others.

Eerily Familiar

Though other two-sun worlds have been discovered in the past, Kepler-1647b is substantially larger, roughly matching the size and composition of Jupiter. The planet has other similarities to those in our solar system as well. Its 4.4-billion-year age is about the same as Earth's, and each of its stars are around the same size as the Sun.

Related: "Saturn On Steroids" Has Massive and Seemingly Impossible Rings

We Finally Found You

Whereas a Jupiter-sized planet would ordinarily be pretty easy to spot with an advanced telescope, confirmation of Kepler-1647b took an unusually long time. Astronomers identify exoplanets by watching them pass in front of their home stars, and this planet's two-star system and its lengthy three-year orbital period made that particularly tricky.

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Watch And Learn: Our Favorite Content About Circumbinary Planets

Astronomers Find Largest Known Planet To Orbit Two Suns

Key Facts In This Video

  1. Astronomers recently discovered the largest planet known to date to orbit two stars. 00:09

  2. It's located 3,700 light years away and is roughly the same age as Earth. 00:20

  3. It's located within the habitable range, but because it's a gas giant, life is unlikely to be present. 00:31

Ask An Astronomer: Can A Planet Have Two Suns?

Written by Curiosity Staff June 29, 2016

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