3I/ATLAS: A 2.6-km Nucleus and Evolving Chemistry Revealed by Hubble and JWST

To the point

Researchers Toni Scarmato, Mauro Barbieri, Man-To Hui, and Matthew Belyakov report that interstellar visitor 3I/ATLAS has a surprisingly large nucleus and a chemically evolving gas signature as it moves away from the Sun, with methane appearing only after perihelion and the CO2/H2O balance shifting, implying a layered surface and subsurface composition and suggesting interstellar wanderers may be more diverse and common than previously thought.