First <i>JWST</i> spectrum of distant activity in long-period comet C/2024 E1 (Wierzchos)
C. Snodgrass, Carrie E. Holt, Michael S. P. Kelley, Cyrielle Opitom, Aurélie Guilbert-Lepoutre, Matthew M. Knight, Rosita Kokotanekova, Emmanuël Jehin, Elena Mazzotta Epifani, A. Migliorini, C. Tubiana, M. Micheli, Davide Farnocchia
Abstract
ABSTRACT We observed the new long-period comet C/2024 E1 (Wierzchos), inbound at 7 au from the Sun, using the Near-Infrared Spectrograph (NIRSpec) integral field unit on JWST. The spectrum shows absorption features due to water ice in the coma and evidence for CO$_2$ driven activity, with a production rate of $Q(\mathrm{ CO}_2) = 2.546 \pm 0.019 \times 10^{25}$ molecules s$^{-1}$, and no emission features of water or CO. The latter is surprising, given that CO is more volatile than CO$_2$, and suggests that this comet may have lost its near-surface CO during its early evolution, before implantation in the Oort cloud.