000008031 001__ 8031
000008031 005__ 20260226110550.0
000008031 0247_ $$2DOI$$a10.1093/mnras/staf826
000008031 037__ $$aSCART-2026-0127
000008031 100__ $$aClark, Nicholas 
000008031 245__ $$aJWST observations of the Ring Nebula (NGC 6720) ─ II. PAH emission
000008031 260__ $$c2025
000008031 520__ $$aPolycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in clumpy circumstellar environments, yet their formation and evolutionary pathways in such environments remain elusive. We aim to characterize the PAH emission in a clumpy planetary nebula to decipher their formation and evolution pathways. We obtained JWST Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI) integral field unit spectroscopic observations of two individual knots in the Ring Nebula (NGC 6720), a clumpy planetary nebula, and determine the PAH spectral characteristics. We detect the 3.3 and 11.2  μ m PAH emission bands in both knots but do not detect PAH emission in the 6─9  μ m range. We supplement our data with Spitzer Infrared Spectrograph (IRS) Short-Low 1 (SL1) and SL2 data, containing 11.2, weak 6.2, and weak 7.7  μ m PAH emission bands. The JWST data confirm the unusual profile of the 11.2  μ m band, which is very broad and redshifted with respect to typical 11.2  μ m PAH profiles. We estimate the PAH population to be largely neutral. The relative integrated surface brightness of the 3.3 and 11.2  μ m bands indicates the presence of small-sized PAHs, consisting of 35  ±  6 carbon atoms. We find that the PAH emission is concentrated outside of the clumps, in the inter-clump medium, and confirm the existence of enhanced PAH emission in a narrow 'PAH ring' centred on the central star. This morphology suggests that PAHs formed during the Ring Nebula's asymptotic giant branch phase, in the central star's dust-driven wind.
000008031 594__ $$aNO
000008031 6531_ $$acircumstellar matter
000008031 6531_ $$astars: evolution; planetary nebulae: general
000008031 6531_ $$aplanetary nebulae: individual: NGC 6720; infrared: stars
000008031 6531_ $$aSolar and Stellar Astrophysics
000008031 6531_ $$aAstrophysics of Galaxies
000008031 700__ $$aPeeters, Els  
000008031 700__ $$aCox, Nick L. J. 
000008031 700__ $$aCami, Jan  
000008031 700__ $$aBarlow, Michael J.  
000008031 700__ $$aKavanagh, Patrick J.  
000008031 700__ $$aVan de Steene, Griet 
000008031 700__ $$aMatsuura, Mikako  
000008031 700__ $$aZijlstra, Albert 
000008031 700__ $$aAleman, Isabel 
000008031 700__ $$aBernard-Salas, Jeronimo 
000008031 700__ $$aDinerstein, Harriet L. 
000008031 700__ $$aJusttanont, Kay 
000008031 700__ $$aKaplan, Kyle F. 
000008031 700__ $$aManchado, Arturo 
000008031 700__ $$aSahai, Raghvendra 
000008031 700__ $$avan Hoof, Peter 
000008031 700__ $$aVolk, Kevin 
000008031 700__ $$aWesson, Roger
000008031 773__ $$c1984-1997$$n2$$pMonthly Notices of the Royal Astronomical Society$$v540$$y2025
000008031 8560_ $$fgriet.vandesteene@ksb-orb.be
000008031 85642 $$ahttps://ui.adsabs.harvard.edu/abs/2025MNRAS.540.1984C/abstract
000008031 905__ $$apublished in
000008031 980__ $$aREFERD