Clark, Nicholas;
Peeters, Els;
Cox, Nick LJ;
Cami, Jan;
Barlow, Michael J;
Kavanagh, Patrick J;
Van de Steene, Griet;
... Wesson, Roger; + view all
(2025)
JWST observations of the Ring Nebula (NGC 6720) – II. PAH emission.
Monthly Notices of the Royal Astronomical Society
, 540
(2)
pp. 1984-1997.
10.1093/mnras/staf826.
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Abstract
Polycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in clumpy circumstellar environments, yet their formation and evolutionary pathways in such environments remain elusive. We aim to characterize the PAH emission in a clumpy planetary nebula to decipher their formation and evolution pathways. We obtained JWST Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI) integral field unit spectroscopic observations of two individual knots in the Ring Nebula (NGC 6720), a clumpy planetary nebula, and determine the PAH spectral characteristics. We detect the 3.3 and 11.2 m PAH emission bands in both knots but do not detect PAH emission in the 6-9 m range. We supplement our data with Spitzer Infrared Spectrograph (IRS) Short-Low 1 (SL1) and SL2 data, containing 11.2, weak 6.2, and weak 7.7 m PAH emission bands. The JWST data confirm the unusual profile of the 11.2 m band, which is very broad and redshifted with respect to typical 11.2 m PAH profiles. We estimate the PAH population to be largely neutral. The relative integrated surface brightness of the 3.3 and 11.2 m bands indicates the presence of small-sized PAHs, consisting of 35 6 carbon atoms. We find that the PAH emission is concentrated outside of the clumps, in the inter-clump medium, and confirm the existence of enhanced PAH emission in a narrow 'PAH ring' centred on the central star. This morphology suggests that PAHs formed during the Ring Nebula's asymptotic giant branch phase, in the central star's dust-driven wind.
| Type: | Article |
|---|---|
| Title: | JWST observations of the Ring Nebula (NGC 6720) – II. PAH emission |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staf826 |
| Publisher version: | https://doi.org/10.1093/mnras/staf826 |
| Language: | English |
| Additional information: | © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Circumstellar matter, stars: evolution, planetary nebulae: general, planetary nebulae: individual: NGC 6720, infrared: stars |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10213236 |
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