Overview
- Spacecraft cameras on SOHO, STEREO and GOES-19 recorded a rapid perihelion surge in brightness and a distinct blue tint while the object was unobservable from Earth.
- New analyses find the brightening followed an exceptionally steep r^-7.5 dependence with color consistent with strong gas emissions rather than dust alone.
- JWST/NIRSpec and SPHEREx report extreme CO2 enrichment (CO2/H2O ≈ 7.6) and substantial CO, supporting models that galactic cosmic rays have processed the outer ~15–20 meters of the nucleus.
- Researchers expect coordinated follow-ups as 3I/ATLAS re-enters dark skies in November–December to test whether activity changes expose less-altered material.
- NASA and many astronomers describe the visitor as a natural comet and say it poses no threat, while high-profile claims of non-gravitational acceleration or a nickel-rich plume remain unconfirmed.