During a special observation run earlier this month, NASA’s TESS space telescope recorded the interstellar comet’s subtle glow and tail, adding to archived observations that may reveal clues about this rare visitor from beyond our Solar System.
This image of 3I/ATLAS was captured by NASA’s TESS satellite on January 15, 2026. Image credit: NASA / Daniel Muthukrishna, MIT.
3I/ATLAS was discovered by the NASA-funded ATLAS survey telescope in Rio Hurtado, Chile, on July 1, 2025.
Also known as C/2025 N1 (ATLAS) and A11pl3Z, the interstellar comet arrived from the direction of the constellation Sagittarius.
Its orbit is the most dynamically extreme of any object yet recorded in the Solar System.
3I/ATLAS reached its closest approach to the Sun — known as perihelion — on October 30, 2025.
The interstellar visitor came within 1.4 AU or 210 million km of our home star — just inside the orbit of Mars.
After emerging from behind the Sun, the comet reappeared in the sky close to Zaniah, a triple-star system located in the constellation of Virgo.
“The TESS spacecraft scans a wide swath of the sky for about a month at a time, looking for variations in the light from distant stars to spot orbiting exoplanets, or worlds beyond our Solar System,” MIT astronomer Daniel Muthukrishna and colleagues said in a statement.
“This technique also allows TESS to identify and monitor comets and asteroids out to large distances.”
“The mission’s wide field of view previously happened to observe 3I/ATLAS in May 2025, almost two months before it was discovered.”
From January 15 to 22, 2026, TESS re-observed the interstellar comet during a special observation run.
The object’s brightness was around 11.5 in apparent magnitude, or approximately 100 times fainter than what humans can see with the unaided eye.
All the TESS data are publicly available on the Mikulski Archive for Space Telescopes.
“Looking back at the TESS data, we were able to identify the faint comet by stacking multiple observations to track its movement,” the astronomers said.
