by Ben Chen
On January 6, 2020, NASA announced that a 17-year-old intern, Wolf Cukier, had discovered a new planet 1,300 light years away from Earth and 6.9 times larger than Earth (as a more helpful reference, the planet is between Neptune and Saturn in size). Discovered using NASA’s TESS (Transiting Exoplanet Survey Satellite), this new planet, TOI 1338 b, is also “about 10% more massive than our Sun” and TESS’s first circumbinary planet, meaning it orbits two stars —specifically, this planet orbits its two stars every 95 days.
Cukier, now a senior at Scarsdale High School in New York, joined NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern in 2019. His assignment was to “examine variations in star brightness captured by NASA’s [TESS program] and uploaded to the Planet Hunters TESS citizen science project,” an initiative wherein individuals can analyze the mass data traffic from TESS. This traffic contains brightness data from 200,000 bright nearby stars, recorded every two minutes to uncover “interesting planetary systems, allowing us to explore the formation and evolutions of these worlds.” Cukier, using this star brightness data from TESS, discovered a new planet on the third day of his NASA internship.
“‘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. ‘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.’”
So how did TESS help Cukier discover this new planet? It starts by searching for exoplanets by “looking at tiny, regular dips in starlight called transits.” Transits can be seen on graphs consisting of brightness data, where brightness is graphed against time. Usually, these tiny dips can then be traced on said graphs using the data found by TESS. In an eclipsing binary, where the stars in a system “circle each other in our plane of view,” there are constant transits caused by the stars eclipsing each other. Now, Cukier’s explanation makes more sense to the layman—the irregular timing of transits led him and other researchers to discover this new planet.
But as NASA describes, “planets orbiting two stars are more difficult to detect than those orbiting one.” Because TOI 1338 b’s transits happen every 93 and 95 days, and also vary in depth and duration due to the orbital motion of its stars, TESS only sees the transits crossing the larger star; the transits of the smaller star are too faint to detect.
Additionally, Cukier’s discovery is even more significant when you consider that he didn’t use computer algorithms to analyze transits on brightness graphs. After all, “‘[t]hese are the types of signals that algorithms really struggle with,’ said lead author Veselin Kostov, a research scientist at the SETI Institute and Goddard. ‘[But,] [t]he human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems.’”
NASA continues, “[t]his explains why Cukier had to visually examine each potential transit. For example, he initially thought TOI 1338 b’s transit was a result of the smaller star in the system passing in front of the larger one — both cause similar dips in brightness. But the timing was wrong for an eclipse.” Therefore, with further analysis and the usage of a software package called “eleanor” created by a team of graduate students at the University of Chicago (to confirm that the transits were legitimate), we are now able to confirm the existence of TOI 1338 b, thanks to 17-year-old Wolf Cuzier. And who knows, by utilizing the technology and knowledge of this era, maybe you’ll be the next Wolf Cukier, discovering more and more about the universe that we live in.
“TESS Satellite Discovered Its 1st World Orbiting 2 Stars.” Video file, 01:32.Youtube. Posted by NASA Goddard, January 6, 2020. Accessed January 11,2020. https://www.youtube.com/watch?v=8FrlhrtVEW8&feature=emb_logo.
Smith, Chris. “TESS Satellite Discovered Its First World Orbiting Two Stars.” NASA Goddard Media Studios. Last modified January 6, 2020. Accessed January 11, 2020. https://svs.gsfc.nasa.gov/13510.
Kazmierczak, Jeanette. “NASA’s TESS Mission Uncovers Its 1st World With Two Stars.” NASA. Last modified January 6, 2020. Accessed January 11, 2020. https://www.nasa.gov/feature/goddard/2020/nasa-s-tess-mission-uncovers-its-1st-world-with-two-stars/.
Rogers, James. “17-year-old NASA intern makes stunning discovery.” Fox News, January 10, 2020, NASA. Accessed January 11, 2020. https://www.foxnews.com/science/17-year-old-nasa-intern-stunning-discovery.
“Planet Hunters TESS.” Zooniverse. Accessed January 11, 2020.https://www.zooniverse.org/projects/nora-dot-eisner/planet-hunters-tess/about/research.