Kepler-1647b, a newly discovered exoplanet identified by researchers at NASA Goddard Space Flight Center and San Diego State University, is the biggest planet discovered outside our Solar System that orbits two suns.
In a galaxy far, far away…
Located 3,700 light-years away in the Cygnus constellation, the new exoplanet is a gas giant that orbits not one, but two stars, making it a rare circumbinary planet (sometimes known as Tatooine planets – think Star Wars). One of these stars is slightly larger than ours and the other slightly smaller.
It was also found that Kepler-1647b is 4.4 billion years old (very similar to Earth) and is roughly the same size as fellow gas giant Jupiter, making it the largest transiting circumbinary planet ever found.
NASA’s Kepler Space Telescope is the chief scout when it comes to searching for new planets, and astronomers use the the data sent back to look for slight dips in the brightness of a star that indicates when a planet is passing, or transiting, in front of it. But circumbinary planet as they are notoriously hard to find, as SDSU astronomer William Welsh, one of the paper’s coauthors, explains: “The transits are not regularly spaced in time and they can vary in duration and even depth.”
Hide and seek
Kepler-1647b was first discovered in 2011 but more data and extended analysis was required to confirm the final transit of the planet. Eventually, it was determined that the planet takes 1,107 days (just over three years) to orbit both of its stars, the longest recorded period of any known transiting exoplanet. It also defies convention by orbiting much further away from its stars than any other known circumbinary planet.
“Kepler-1647b is important because it is the tip of the iceberg of a theoretically predicted population of large, long-period circumbinary planets,” says Welsh.
The exoplanet also exists within the habitable, or goldilocks zone, where conditions are theoretically suitable for life to develop, though as Kepler-1647b is a gas giant the existence of life very unlikely. However, large moons that might be orbiting Kepler-1647b could be potential candidates for extraterrestrial life.