Overview
- Astronomers using the Subaru Telescope measured 3I/ATLAS after perihelion on January 7th, finding a carbon dioxide to water ratio lower than earlier space-telescope estimates.
- They derived the ratio from the color of the coma and from faint oxygen emission lines, which reveal how sunlight breaks apart water and carbon dioxide.
- The coma is gas that vents from the nucleus, and the shift is consistent with different ices releasing as the Sun’s heat reached deeper layers.
- The team’s analysis applies methods honed on Solar System comets to this interstellar visitor to track how its volatile mix changed over time.
- The study is in press at The Astronomical Journal with publication listed for April 22nd, and researchers expect future survey telescopes to uncover more interstellar objects for direct comparison.