Journal Club
JCMT detection of HCN emission from 3I/ATLAS at 2.1 au
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Europe/Rome
Aula Japelli (Dipartimento di Fisica e Astronomia - Edificio ex-Rizzato)
Aula Japelli
Dipartimento di Fisica e Astronomia - Edificio ex-Rizzato
Description
Speakers: Alessandra Mura (INAF-Università degli Studi di Padova)
We report the detection of HCN(J=3−2) rotational emission from comet 3I/ATLAS at a heliocentric distance of 2.13 au with the James Clerk Maxwell Telescope (JCMT). Observations were conducted between 2025 August 7 and 2025 September 14 (UT) using the ′U¯¯¯¯′u¯¯¯ heterodyne receiver and ACSIS (Auto Correlation Spectral Imaging System) spectroscopic backend. The HCN line was detected at >6σ on 2025 September 14 (UT) and a production rate of Q(HCN)=(4.0±1.7)×1025 s−1 was derived by non-LTE radiative transfer modelling. Preliminary estimates of the HCN/H2O and CN/HCN abundance ratios suggest values similar to Solar system comets.