Planets orbiting binary systems are an exciting curiosity and NASA’s Transiting Exoplanet Survey Satellite (TESS) has found its first one. What’s even more exciting is that the discovery was made by teenager Wolf Cukier on his third day of a NASA internship last summer.
The planet's new name is TOI 1338 b and it is 6.9 times larger than Earth, coming between us and the star between every 93 and 95 days. Cukier’s job during the internship was to examine data from TESS uploaded to the Zooniverse citizen science portal. Users help researchers find new planets and the 17-year-old managed to do just that.
“I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said in a statement. “About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”
TOI 1338 consists of a star 10 percent heavier than the Sun and a second one about one-third of the mass of our own star. The two stars orbit each other every 15 days, taking turns to get in front of each other from our perspective. These systems are known as eclipsing binaries.
But Cukier spotted another type of eclipse. TOI 1338 b is between the size of Neptune and Saturn, so whenever it passed in front of the star, TESS reported a dip in the brightness we got from the system. The signal was small for the larger star and undetectable for the smaller star, but it was enough to pique the attention of the young researcher.
“These are the types of signals that algorithms really struggle with,” added Veselin Kostov, a research scientist at the SETI Institute and Goddard Space Flight Center and lead author of the upcoming paper on the planet. “The human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems.”
TESS monitors millions of stars, taking photographs of the same patch of sky every 30 minutes for 27 days. Previous planet-hunting missions from NASA, Kepler and K2, have discovered 12 planets like TOI 1338 b. TESS is expected to discover hundreds of thousands of eclipsing binaries so this might be the first planet orbiting binary stars for the mission but it won’t be the last.
The TOI 1338 system is located 1,300 light-years away in the constellation Pictor.