3I/ATLAS was found by the NASA-funded ATLAS study telescope in Rio Hurtado, Chile, on July 1, 2025.

Understood as C/2025 N1 (ATLAS) and A11pl3Z, the interstellar comet got here from the instructions of the constellation Sagittarius.

Its orbit is the most dynamically severe of any item yet taped in the Solar System.

3I/ATLAS reached its closest technique to the Sun– referred to as perihelion– on October 30, 2025.

The interstellar visitor came within 1.4 AU or 210 million km of our home star– simply inside the orbit of Mars.

After emerging from behind the Sun, the comet came back in the sky near to Zaniah, a triple-star system situated in the constellation of Virgo.

” The TESS spacecraft scans a broad swath of the sky for about a month at a time, trying to find variations in the light from remote stars to identify orbiting exoplanets, or worlds beyond our Solar System, “MIT astronomer Daniel Muthukrishna and associates stated in a declaration.

“This method likewise permits TESS to recognize and keep track of comets and asteroids out to big ranges.”

“The objective’s broad field of vision formerly occurred to observe 3I/ATLAS in May 2025, nearly 2 months before it was found.”

From January 15 to 22, 2026, TESS re-observed the interstellar comet throughout an unique observation run.

The things’s brightness was around 11.5 in evident magnitude, or around 100 times fainter than what people can see with the unaided eye.

All the TESS information are openly offered on the Mikulski Archive for Space Telescopes.

“Looking back at the TESS information, we had the ability to recognize the faint comet by stacking numerous observations to track its motion,” the astronomers stated.