First JWST spectrum of distant activity in Long Period Comet C/2024 E1 (Wierzchos)

Abstract

We observed the new Long Period Comet C/2024 E1 (Wierzchos), inbound at 7 au from the Sun, using the 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 $Q(C{O}_2)=2.546\pm 0.019\times 10^{25}$ 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.

6 pages, accepted for publication in MNRAS