Astronomers utilized a Gemini Multi-Object Spectrometer (GMO) at the Gemini South Telescope, part of the NSF’s International Gemini Observatory in the Chilean Andes, to capture new multi-color images of the interstellar comet 3i/Atlas.

This image of 3i/Atlas was captured by the Gemini Multi-Object Spectrograph (GMO) on August 27, 2025 at the Gemini South Telescope. Image credit: International Gemini Observatory / NSF / AURA / Shadow The Scientist / J. Miller Array / M. M. Rodriguez, nsf/crask of rects Anchorage & Noirlab/M. Zamani, NSF’s Noirlab.

3i/Atlas was identified on July 1, 2025, by a NASA-supported Atlas (Asteroid Ground Shock Last Alert System) Survey Telescope in Riojartad, Chile.

The comet is anticipated to approach the Sun at a distance of 1.4 AU (210 million km, or 130 million miles) around October 30, 2025.

The latest images from Gemini/GMOS reveal a broad coma and tail extending roughly 1/120th of a degree across the sky, away from the Sun.

These features appear significantly more pronounced compared to earlier images of the comet, indicating that 3i/Atlas is becoming increasingly active as it traverses the inner solar system.

Recent observations also imply that the dust and ice from the comet closely resemble those of solar comets, suggesting a commonality in the processes that govern the formation of planetary systems around other stars.

“As 3i/Atlas journeys back into the depths of interstellar space, these images serve as both scientific milestones and enigmatic clues,” states Dr. Karen Meech, an astronomer from the Institute of Astronomy at the University of Hawaii.

“They remind us that our solar system is merely a fragment of a vast, dynamic galaxy, where even transient visitors can leave a lasting impact.”

Alongside capturing a stunning image, the primary scientific aim of the observation session was to obtain the comet’s spectrum, which corresponds to the wavelengths of the emitted light.

The resulting spectra provide critical insights into the composition and chemistry of the comet, enabling scientists to understand its changes as it navigates through the solar system.

“The main goal was to observe the color of the comet to glean information about the composition and size of the coma dust particles, as well as to obtain the spectrum for direct chemical analysis,” noted Dr. Mace.

“We were thrilled to witness the growth of the comet’s tail and to see our first hints of chemistry from the spectrum, indicating particle changes since earlier Gemini observations.”

“These observations yield both awe-inspiring visuals and invaluable scientific data,” asserts Dr. Bryce Bolin, a researcher at Eureka Scientific.

“Each interstellar comet acts as a messenger from another stellar system, and by examining its light and color, we can begin to appreciate the diversity of worlds beyond our own.”