Wolf Cukier, a junior at Scarsdale High School in New York, got a two-month internship with NASA during his junior year. So he went to NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

His first task was to investigate fluctuations in star brightness acquired by NASA’s Transiting Exoplanet Survey Satellite, or TESS, as part of the Planet Hunters TESS citizen science initiative. (The citizen science initiative lets people who do not work for NASA to assist in the discovery of new planets.)

Cukier found a new planet only three days into his internship. NASA made the announcement on their website, after validating the teenager’s work, submitting a paper co-authored by Cukier for scientific review, and announcing the finding of the planet, now known as “TOI 1338 b,” during the 235th American Astronomical Society conference.

17-year-old Cukier said: “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. 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.

I noticed a dip, or a transit, from the TOI 1338 system, and that was the first signal of a planet. I first saw the initial dip and thought, ‘Oh that looked cool,’ but then when I looked at the full data from the telescope at that star, I, and my mentor also noticed, three different dips in the system.”

TOI 1338 b is 6.9 times the size of Earth (between Neptune and Saturn) and is situated in the constellation Pictor, approximately 1,300 light-years distant from Earth. TOI 1338 b is the first circumbinary planet discovered by the TESS system, which means it circles two stars. The two stars orbit each other every 15 days, and one of them is 10% the size of the Sun. TOI 1338 b and its two stars form what is known as an “eclipsing binary.”

According to NASA, circumbinary planets like TOI 1338 b are difficult to discover since standard algorithms might misinterpret them for eclipses, which is why interns like Cukier are crucial.

After making history, the high school senior is now considering his college options. Princeton, MIT, and Stanford are his top three options.