JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution
Abstract
Polycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in Oxygen-rich planetary nebulae (PNe), yet their formation and evolution in these environments is an open question. We aim to study the formation and evolution of the PAHs in the O-rich PN NGC 6302, by characterizing the PAH emission throughout this object. We obtained JWST MIRI IFU spectroscopic observations of NGC 6302 pointed at its central source. From these, we extract four template spectra that are representative of the variation in PAH emission throughout NGC 6302. We detect the major PAH features at 6.2, 7.7, 8.6, 11.2, and 12.7 μm, and several minor PAH features. The template spectra vary in terms of their PAH feature widths, peak wavelengths, and relative intensities. The 11.2 μm PAH feature is class B, typical for PNe. The 6-9 μm PAH features are class A, which is less common for PNe. We estimate the PAH charge to be 75% cations on average, based on the 7.7/11.2 PAH feature ratio. The relative strengths of the 11-15 μm PAH features indicate a range of PAH edge structures. To ensure consistency in our observations and explain variable PAH feature widths, we propose a variation in the size of the PAHs throughout NGC 6302, and suggest variation in the shielding of these PAHs. The PAHs range from large and non-compact, to small and compact. We find that NGC 6302 formed PAHs in-situ in the current PN phase, likely from small hydrocarbons formed by the photodissociation of CO.
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BibTeX
@misc{clark2026jwst,
title = {{JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution}},
author = {Nicholas Clark and Els Peeters and Jan Cami and Mikako Matsuura and Alexander G. G. M. Tielens and Patrick J. Kavanagh and Michael J. Barlow and Joel Kastner and Kathleen E. Kraemer and Hektor Monteiro and Raghvendra Sahai and G. C. Sloan and N. C. Sterling and Jeremy R. Walsh and L. B. F. M. Waters and Nicholas J. Wright and Isabel Aleman and Bruce Balick and Jeronimo Bernard-Salas and Charmi Bhatt and Joris Blommaert and Harriet L. Dinerstein and Naomi Hirano and Olivia Jones and Francisca Kemper and Eric Lagadec and Paula Moraga Baez and Maryam Torki and Peter A. M. van Hoof and Kevin Volk and Roger Wesson and Albert Zijlstra},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30441},
eprint = {2610.30441},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30441},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution
AU - Nicholas Clark
AU - Els Peeters
AU - Jan Cami
AU - Mikako Matsuura
AU - Alexander G. G. M. Tielens
AU - Patrick J. Kavanagh
AU - Michael J. Barlow
AU - Joel Kastner
AU - Kathleen E. Kraemer
AU - Hektor Monteiro
AU - Raghvendra Sahai
AU - G. C. Sloan
AU - N. C. Sterling
AU - Jeremy R. Walsh
AU - L. B. F. M. Waters
AU - Nicholas J. Wright
AU - Isabel Aleman
AU - Bruce Balick
AU - Jeronimo Bernard-Salas
AU - Charmi Bhatt
AU - Joris Blommaert
AU - Harriet L. Dinerstein
AU - Naomi Hirano
AU - Olivia Jones
AU - Francisca Kemper
AU - Eric Lagadec
AU - Paula Moraga Baez
AU - Maryam Torki
AU - Peter A. M. van Hoof
AU - Kevin Volk
AU - Roger Wesson
AU - Albert Zijlstra
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.30441
UR - https://arxiv.org/abs/2610.30441
AB - Polycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in Oxygen-rich planetary nebulae (PNe), yet their formation and evolution in these environments is an open question. We aim to study the formation and evolution of the PAHs in the O-rich PN NGC 6302, by characterizing the PAH emission throughout this object. We obtained JWST MIRI IFU spectroscopic observations of NGC 6302 pointed at its central source. From these, we extract four template spectra that are representative of the variation in PAH emission throughout NGC 6302. We detect the major PAH features at 6.2, 7.7, 8.6, 11.2, and 12.7 μm, and several minor PAH features. The template spectra vary in terms of their PAH feature widths, peak wavelengths, and relative intensities. The 11.2 μm PAH feature is class B, typical for PNe. The 6-9 μm PAH features are class A, which is less common for PNe. We estimate the PAH charge to be 75% cations on average, based on the 7.7/11.2 PAH feature ratio. The relative strengths of the 11-15 μm PAH features indicate a range of PAH edge structures. To ensure consistency in our observations and explain variable PAH feature widths, we propose a variation in the size of the PAHs throughout NGC 6302, and suggest variation in the shielding of these PAHs. The PAHs range from large and non-compact, to small and compact. We find that NGC 6302 formed PAHs in-situ in the current PN phase, likely from small hydrocarbons formed by the photodissociation of CO.
ER -