NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter has returned groundbreaking ultraviolet (UV) images of the interstellar comet 3I/ATLAS, providing scientists with unique insights into its chemical makeup and water vapor release. This marks the first time such detailed UV observations have been obtained for this particular comet, potentially unlocking new understandings of interstellar objects.
Unique Imaging Technique
Between September 27 and October 7, 2025, MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) camera captured 3I/ATLAS using a novel technique. IUVS took multiple images across various UV wavelengths – akin to using different filters on a standard camera – to analyze the comet’s composition.
The orbiter also generated high-resolution UV images specifically to track hydrogen emissions from the comet, allowing scientists to map the distribution of key molecules. By combining these images, researchers are able to identify and quantify a range of substances within the comet’s coma (the diffuse envelope surrounding its nucleus).
What This Means for Science
The significance lies in the comet’s interstellar origin. Unlike comets born within our solar system, 3I/ATLAS originated from outside, potentially carrying clues about the conditions in other star systems. The IUVS data includes an estimated upper limit for the ratio of deuterium (a heavier hydrogen isotope) to regular hydrogen – a critical indicator of the comet’s formation environment.
“The images MAVEN captured truly are incredible,” said MAVEN’s principal investigator Dr. Shannon Curry. “The detections we are seeing are significant, and we have only scraped the surface of our analysis.”
Unveiling Origins and Evolution
By mapping atoms and molecules such as hydrogen and hydroxyl within the comet’s coma, scientists aim to reconstruct its journey and origins. The data could reveal details about the comet’s formation, its interactions with interstellar space, and how it has evolved over time.
“There was a lot of adrenaline when we saw what we’d captured,” added MAVEN’s deputy principal investigator Dr. Justin Deighan. “Every measurement we make of this comet helps to open up a new understanding of interstellar objects.”
The ongoing analysis of 3I/ATLAS’s chemical makeup is expected to refine our understanding of interstellar comets and, by extension, the conditions in which they form. This research is vital for broadening our knowledge of planetary systems beyond our own.
