The characterization continues. With the trajectory well-determined over a long arc, we check and recheck spectral bands and lines (therefore, compositions):
Astrophysics > Earth and Planetary Astrophysics arxiv.org/abs/2510.02817
[Submitted on 7 Oct 2025]
Coulson, I. M. Kuan, Y-J. Charnley, S. B. JCMT Detection of HCN emission from 3I/ATLAS at 2.1 AU
We have another spectral scan of our interstellar arrival. Again, cyanide and cyano-compounds (here, hydrogen cyanide) are present in comets, and visible in their spectra. This work then complements and corroborates prior entries. In particular, the authors turned to the cyano spectral feature in the submillimeter, thereby giving independent evidence, as well as tracking the ramp-up of emissions (at least, of that volatile) as the comet nears the Sun and warms.
Also note that Coulson et al. give the emission levels (at least, of this volatile) as nearing those of typical, Solar System comets. It would be interesting to see how well the different research groups can constrain levels.