Near Infrared study of comet C/2022 E3(ZTF) using iSHELL spectrograph at NASA-IRTF

Abstract

We present a comprehensive analysis of the chemical composition of the Oort Cloud Comet C/2022 E3 (ZTF), in the near-infrared (near-IR) wavelength regime. Observations were conducted using the iSHELL high-resolution spectrograph (R~50000) at the NASA Infrared Telescope Facility (IRTF) on UT 2023 January 20 and January 22, during the comet’s post-perihelion passage. We report rotational temperatures, production rates, and mixing ratios (relative to H2O and C2H6) for the primary volatiles: CH3OH, HCN, CH4, CO, and H2CO. Additionally, we place stringent 3 upper limits on the production rates of NH3, and C2H2. The spatial emission profiles of these outgassing species are also examined to understand their release mechanisms and source regions. A comparative analysis was performed between the results obtained in this work and other observations of E3 (ZTF), as well as data from other comet families, to place the findings in a broader compositional context. Based on this comparison, a taxonomic classification has been conducted of the detected volatiles. Compared to other family of comets, the abundances of CH3OH and C2H6 were found to be typical, whereas other volatile species exhibited significant depletion.