A JWST Study of Stardust. II. Polycyclic Aromatic Hydrocarbons in Comet 81P/Wild 2 and Implications for Primitive Solar System Carbon
Abstract
We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance (rH) of 1.85 au using the NIRSpec and MIRI integral field unit spectrographs on board the James Webb Space Telescope (JWST). This study is the first compositional comparison between JWST remote-sensing spectroscopy of a solar system object against terrestrial analysis of its returned samples. Recent work determined contributions of molecular emission from coma volatiles and thermal emission from the nucleus and coma dust grains to these spectra. Subtracting the molecular and thermal emission models produces a residual spectrum with a clear resonance near 3.37 μm and multiple others spanning the $6 - 12$ μm region. Analysis of these residuals provides strong evidence for the presence of polycyclic aromatic hydrocarbons (PAHs) in the coma of 81P/Wild 2. The resulting PAH populations reflect material incorporated into the nucleus of 81P/Wild 2 that was inherited from the diffuse interstellar medium, the interstellar medium, and the protoplanetary disk. The PAHs sensed by JWST are compared to those detected in laboratory analyses of the Stardust mission returned samples.
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BibTeX
@misc{roth2026jwst,
title = {{A JWST Study of Stardust. II. Polycyclic Aromatic Hydrocarbons in Comet 81P/Wild 2 and Implications for Primitive Solar System Carbon}},
author = {Nathan X. Roth and Stefanie N. Milam and Diane H. Wooden and Els Peeters and Charles E. Woodward and Dominique Bockelee-Morvan and Michael S. P. Kelley and Steven B. Charnley and Simon J. Clemett and Martin A. Cordiner and Perry A. Gerakines and David E. Harker and Ella Sciamma-O'Brien and Geronimo L. Villanueva},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.34116},
eprint = {2609.34116},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.34116},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A JWST Study of Stardust. II. Polycyclic Aromatic Hydrocarbons in Comet 81P/Wild 2 and Implications for Primitive Solar System Carbon
AU - Nathan X. Roth
AU - Stefanie N. Milam
AU - Diane H. Wooden
AU - Els Peeters
AU - Charles E. Woodward
AU - Dominique Bockelee-Morvan
AU - Michael S. P. Kelley
AU - Steven B. Charnley
AU - Simon J. Clemett
AU - Martin A. Cordiner
AU - Perry A. Gerakines
AU - David E. Harker
AU - Ella Sciamma-O'Brien
AU - Geronimo L. Villanueva
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.34116
UR - https://arxiv.org/abs/2609.34116
AB - We report observations of comet 81P/Wild 2, target of the Stardust sample return mission, on UT 2023 March 20 and 24 at a heliocentric distance (r_H) of 1.85 au using the NIRSpec and MIRI integral field unit spectrographs on board the James Webb Space Telescope (JWST). This study is the first compositional comparison between JWST remote-sensing spectroscopy of a solar system object against terrestrial analysis of its returned samples. Recent work determined contributions of molecular emission from coma volatiles and thermal emission from the nucleus and coma dust grains to these spectra. Subtracting the molecular and thermal emission models produces a residual spectrum with a clear resonance near 3.37 μm and multiple others spanning the $6 - 12$ μm region. Analysis of these residuals provides strong evidence for the presence of polycyclic aromatic hydrocarbons (PAHs) in the coma of 81P/Wild 2. The resulting PAH populations reflect material incorporated into the nucleus of 81P/Wild 2 that was inherited from the diffuse interstellar medium, the interstellar medium, and the protoplanetary disk. The PAHs sensed by JWST are compared to those detected in laboratory analyses of the Stardust mission returned samples.
ER -