Shinnaka team publishes findings on Interstellar Comet 3I/ATLAS chemistry changes
Updated
Updated · Big Island Video News · May 4
Shinnaka team publishes findings on Interstellar Comet 3I/ATLAS chemistry changes
3 articles · Updated · Big Island Video News · May 4
Using Subaru Telescope observations from Maunakea on 7 January 2026, the researchers found a lower post-perihelion carbon-dioxide-to-water ratio than earlier space-telescope estimates.
The shift suggests solar heating exposed different layers of the comet’s nucleus, changing the gases released and offering a rare comparison between interstellar material and Solar System comets.
Published in The Astronomical Journal on 22 April, the study concerns only the third known interstellar object and may help future surveys such as LSST study more visitors from other star systems.
What did this comet's core reveal about alien worlds after shedding its ancient outer layer near our Sun?
How will the coming flood of interstellar objects reshape our understanding of how planets form across the galaxy?
Dramatic Shift in CO₂/H₂O Ratio Unveils Layered Nucleus Structure of Interstellar Comet 3I/ATLAS
Overview
In late 2025, observations showed interstellar comet 3I/ATLAS had an unusually high carbon dioxide to water ratio, indicating a surface rich in volatile ices. After its close pass by the Sun, intense solar heating vaporized this outer layer, revealing deeper, water-ice-rich layers with new molecules like methanol and cyanogen. This shift uncovered a chemically layered nucleus formed billions of years ago around a low-metallicity star in the Milky Way's thick disk. The comet's extreme isotopic signatures and ancient origin make it a rare time capsule, challenging traditional views of comet composition and reshaping our understanding of planetesimal formation across the galaxy.