JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution

Clark, Nicholas, Peeters, Els, Cami, Jan, Matsuura, Mikako ORCID: https://orcid.org/0000-0002-5529-5593, Tielens, Alexander G. G. M., Kavanagh, Patrick J., Barlow, Michael J., Kastner, Joel, Kraemer, Kathleen E., Monteiro, Hektor, Sahai, Raghvendra, Sloan, G. C., Sterling, N. C., Walsh, Jeremy R., Waters, L. B. F. M., Wright, Nicholas J., Aleman, Isabel, Balick, Bruce, Bernard-Salas, Jeronimo, Bhatt, Charmi, Blommaert, Joris, Dinerstein, Harriet L., Hirano, Naomi, Jones, Olivia, Kemper, Francisca, Lagadec, Eric, Baez, Paula Moraga, Torki, Maryam, van Hoof, Peter A. M., Volk, Kevin, Wesson, Roger and Zijlstra, Albert 2026. JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution. Monthly Notices of the Royal Astronomical Society , stag1992. 10.1093/mnras/stag1992

PDF - Accepted Post-Print Version Available under License Creative Commons Attribution. Download (5MB)

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 (the Butterfly Nebula), 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.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Physics and Astronomy Schools > Physical, Chemical & Environmental Sciences
Publisher:	Oxford University Press
ISSN:	0035-8711
Date of First Compliant Deposit:	30 October 2026
Last Modified:	30 Oct 2026 11:15
URI:	https://orca.cardiff.ac.uk/id/eprint/190545

Actions (repository staff only)

Edit Item