A Multi-Wavelength Study of Comet C/2022 E3 (ZTF): Complementary ALMA and JWST Investigations of Water and Methanol in Cometary Comae

TL;DR

This study combines JWST and ALMA observations to analyze water and methanol in comet C/2022 E3 (ZTF), revealing spatial variations and temperature distributions that inform our understanding of cometary chemistry and its inheritance from the early Solar System.

Contribution

It presents the first simultaneous multi-wavelength analysis of water and methanol in a long-period comet using JWST and ALMA, providing new insights into spatial temperature variations and chemical distributions.

Findings

Modeled values are consistent between JWST and ALMA within error margins.

Detected a statistically significant temperature enhancement in the anti-Sunward direction.

Observed declining water rotational temperatures with distance explained by rotational line cooling.

Abstract

Long-period comets, which are often considered to be representative of material in the protoplanetary disk that formed the Solar System, are ideal to investigate the question of chemical inheritance in astronomy. Determining the chemistry of comets, both individually and as a population, has become of great importance in comparative studies against sources representative of evolutionary precursors to planetary systems. Contemporaneous observations of long-period comet C/2022 E3 (ZTF) were obtained with the JWST and the Atacama Large Millimeter/submillimeter Array (ALMA) in early 2023 March. This work focuses on \ce{CH3OH} measurements from both ALMA and JWST as well as \ce{H2O} measurements from JWST. Radiative transfer modeling of \ce{CH3OH} and \ce{H2O} was performed to investigate spatial variations in rotational temperature, column density, and production rates, as well as a comparison of derived values between the two telescopes. Most of the spatial distributions of the modeled values are centrally peaked, and the modeled values from JWST are all within the error bars of the average values from ALMA. C/2022 E3 (ZTF) also displays an enhancement in modeled rotational temperature in the anti-Sunward direction that is shown to be statistically significant. Based on non-LTE radiative transfer modeling, the declining \ce{H2O} rotational temperatures as a function of nucleocentric distance observed by JWST can be explained primarily as a result of rotational line cooling. The values derived in this work are in general agreement with single-dish millimeter-wave observations.