Double trouble

Look: Scientists discover rare planet orbiting 2 suns

This real-life scenario resembles Tatooine from Star Wars.

by Jennifer Walter
NASA via YouTube

When Star Wars: A New Hope premiered in 1977, the idea that a planet like Tatooine could orbit two suns was the stuff of fantasy.

Sunset Boulevard/Corbis via Getty Images

NASA's Goddard Space Flight Center/Chris Smith (USRA)

But in recent decades, astronomers have located 14 Tatooine-like planets in the universe. Technically known as circumbinary planets, these orbit pairs of stars.

Spying one of these bodies is a rare treat.

They typically take a while to find, but a planet described on November 10 in The Astronomical Journal was spotted in record time.

Lynette Cook

PSI/Pamela L. Gay

The study authors described a system with a newly-identified planet called TIC 172900988 b. It has roughly the same diameter as Jupiter.

But it’s also estimated to be several times as massive as the gas giant Jupier, and extremely hot — though precise measurements have yet to be determined.

NASA/JPL-Caltech

NASA/JPL-Caltech

From Earth, it can be tricky to tell when a planet is orbiting a pair of binary stars.

NASA via YouTube

Researchers have to watch for small changes in the amount of light a star emits to detect a planet passing in front of it.

Things get more complicated when there are two stars instead of one.

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“Transits will not happen with the same interval over the same star. The planet may transit one star and then transit the other before transiting the first star again, and so on.”

Nader Haghighipour, study co-author

The observation process can also take a long time because the orbits of circumbinary planets are longer than bodies orbiting just one star.

NASA via YouTube
For TIC 172900988 b, one trip around its suns is 200 Earth days.

When using NASA’s Transiting Exoplanet Survey Satellite (TESS), researchers only had about 30 days to observe the star system before it focused on another part of the sky.

NASA

NASA

For the first time, researchers were able to spot a planet by using roughly a month’s worth of data from TESS.

They saw that TIC 172900988 b passed in front of each of its stars in about five days.

MARK GARLICK/SCIENCE PHOTO LIBRARY/Science Photo Library/Getty Images

The study reports new techniques for spotting these types of planets that could open the door to discovering even more Tatooine-like planets.

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