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www.astronomerstelegram.org/?read=17664
Mugrauer, M. Belger, M. Jamil, Z. et al. Follow-up Imaging Observations of the Interstellar Comet 3I/ATLAS
ATel #17664 on 10 Feb 2026; 13:40 UT
Yes, it’s a comet. We continue to track the small body, both in the velocity sense, and in the activity sense. The comet has passed perihelion, and is literally receding from the Sun and cooling. However, the falloff in activity (mass loss, via both gas sublimation and its entrained dust) hasn’t really happened yet. This is not unusual; comets take time to warm up and cool down, just like athletes or anything else. On the inbound leg, ATLAS hadn’t really activated much, indicating some sort of insulating mantle. Now, outbound, it’s staying active (well, for ATLAS) now that the protective layer has been violated.