Using Gemini Mult-OBJECT SICTROGRAPH (GMOS) on the Southern Gemini Telescope at the NSF International Gemini Observatory in the Chilean Andes Mountains, astronomers took new multi-colored images from the comet between the 3i/Atlas stars.
This image was taken from 3i / Atlas by Gemini Mult-OBJECT SICTROGRAPH (GMOS) on the Southern Gemini telescope on August 27, 2025. NSF’s Noirb / M. Zamani, NSF’s Noirlab.
3i/Atlas was discovered by NASA scanning (NASA’s last alert system) in Rio Hortado, Chile, on July 1, 2025.
The comet will reach its nearest approach to the sun on around 30 October 2025, at a distance of 1.4 AU (210 million km, or 130 million miles) – within the orbit of Mars.
In the new Gemini/GMOS images, GMOS shows a wide coma and a tail that spans about 1/120 degree in the sky and indicates away from the sun.
These features extend significantly from what appeared in the previous photos of the comet, indicating that 3i/atlas has become more active while traveling through the internal solar system.
The new notes also indicate that dust and ice in the comet are very similar to the comets of the solar system, which is alluding to joint operations in the formation of planetary systems around other stars.
“With 3i/Atlas return to the depths of the space between the stars, these pictures are a scientific teacher and a source of wonder,” said Dr. Karen Mitch, an astronomer at the Institute of Astronomy at Hawaii University.
“It reminds us that our solar system is just one part of a vast and dynamic galaxy – and that even the most passing visitors can have a permanent effect.”
More than just taking amazing images, the main scientific motivation for the observation session was to collect the guilty spectrum, which indicates the wavelengths of the light from which they emit.
The spectrum can tell scientists information about the composition of the comet and chemistry, which allows them to understand how to change the comet while passing through the solar system.
“The basic goals of the notes were to look at the colors of the comet, which provide evidence of the formation and sizes of dust particles in the coma, and to take spectra for a direct evaluation of chemistry,” said Dr. Mitch.
“We were excited to see the growth of the tail, indicating a change in the molecules of previous Gemini, and we got the first glimpse of chemistry from the spectrum.”
“These observations provide a stunning view and critical scientific data,” said Dr. Price Paulin, a researcher at Yorica Scientific, said.
“Every guilty among the stars is a messenger from another stars system, and through the study of light and color, we can begin to understand the diversity of worlds outside our scope.”