The Largest ‘Tatooine’ Planet With 2 Suns Has Just Been Discovered

Some worlds have more than one sun in their sky. Scientists have now confirmed the discovery of a gas giant with the same mass and radius as Jupiter, orbiting a pair of binary stars, making it the largest to be found to date.

Using the Kepler Space Telescope, a team of astronomers from NASA’s Goddard Space Flight Center and San Diego State University (SDSU) were able to identify the new planet, Kepler-1647 b. Planets that orbit two stars are called circumbinary planets; however, some call them “Tatooine” planets, after Luke Skywalker’s homeland in Star Wars.

To discover planets, astronomers look for slight dips in brightness, which indicate there may be a planet transiting in front of a star, blocking some of the star’s light. NASA’s Kepler telescope has been instrumental in this process.

William Welsh, an astronomer from San Diego State University and one of the paper’s co-authors, said in a statement:

After astronomers find a candidate, advanced computer programs are then used to determine if it really is a planet. Laurance Doyle, an astronomer from the SETI Institute and also a co-author on the paper, was the first to notice a transit in 2011. However, to confirm the transit was caused by a circumbinary planet, astronomers needed more data and several years of analysis before they could make the conformation.

Graphic showing Kepler-1647b's size compared to that of all other two-star planets discovered by NASA's Kepler space telescope to date. (Image: Lynette Cook)

Graphic showing Kepler-1647b’s size compared to that of all other 2-star planets discovered by NASA’s Kepler space telescope to date. (Image: Lynette Cook)

A network of amateur astronomers in the KELT Follow-Up Network also provided additional observations, which helped researchers to estimate the planet’s mass. Kepler-1647 b is approximately 4.4 billion years old, which is roughly the same age as the Earth, and sits 3,700 light-years away. The planet stars are similar to our sun, although one is slightly larger, and the other is slightly smaller.

SDSU astronomer Jerome Orosz, another co-author on the study, said:

The giant takes 1,107 days (a little over 3 years) to orbit its host stars, making it the longest period of all confirmed exoplanets. Kepler-1647 b is also much further away from its stars than any other circumbinary planet (circumbinary planets have a tendency to have close-in orbits).

This puts the exoplanet within the so-called habitable zone; however, because Kepler-1647 b is a gas giant, it is unlikely to host any life. “Yet if the planet has large moons, they could potentially be suitable for life,” SDSU wrote.

Follow us on Twitter or subscribe to our weekly email.

Brown Dwarf Flashes Brighter Than the Sun’s Most Powerful Flares
Aerosols Found to Strengthen Storms