Overview
- University of Michigan–led researchers report in Nature Astronomy that 3I/ATLAS contains about 30 times more deuterated, or heavy, water than comets from our solar system.
- ALMA radio antennas in Chile detected the spectral line of HDO (heavy water) in the comet’s coma, while models using methanol measurements were used to estimate the amount of ordinary water.
- Deuterium enrichment of this size forms at temperatures below roughly 30 Kelvin, which signals a birthplace in an extremely cold, low-radiation environment unlike the one that formed the Sun.
- 3I/ATLAS is only the third confirmed interstellar visitor ever observed, giving scientists a rare, direct sample of chemistry from another planetary system.
- Because ALMA can observe close to the Sun, astronomers captured the comet’s gases shortly after its closest solar approach, offering a clear look at its native ice chemistry and refining ideas about how and where planetary systems can form.