Courtesy of our friends Astronomers’ Telegram:
https://www.astronomerstelegram.org/?read=17561
Bolin, B. Wong, I. Abron, L-M. et al. Gemini post-perihelion visible photometry and spectroscopy of interstellar comet 3I/ATLAS
ATel #17561 24 Dec 2025; 20:36 UT
The Gemini North telescope in Hawaii turned to our interstellar visitor recently- very recently, hence ATel. This result is too recent to have gone through thorough peer review and verification. But it’s a pretty cut-and-dried report of telescope observations; screwing up four-color imagery and a basic spectrum would be a truly embarassing screwup indeed. So, what do the imagery and spectrum say? Well, it’s a comet- there’s a coma and tail, moderate as they may be. ATLAS is no Hyakutake or McNaught. The spectrum gives us the volatiles in that coma/tail, but only those with spectral emission in the visible band of the instrument, not water. Yes, ATLAS is now warm, and shedding volatiles like comets do.