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11 November 2025 at 11:31 am
#632065
Participant
The green glow from the coma, presumably Swan band emission from C2 in that image is interesting. This is of course very typical of most comets but spectra taken on approach suggested it was very deficient in C2 relative to CN. See page 9 of this paper
https://arxiv.org/pdf/2509.01647
The ratio may have increased since though, as happened with 2I/Borisov. (I would love to try for a spectrum but the weather here has been hopeless the past month or more with little sign of improvement)
Cheers
Robin
