PAH and H2 emission in the Ring Nebula

11th Pacific Rim Conference on Stellar Astrophysics: Physics and Chemistry of the Late Stages of Stellar Evolution

物理学;天文学

Cox, N.L.J.^1,2 ; Pilleri, P.^1,2 ; Berné, O.^1,2 ; Cernicharo, J.^3 ; Joblin, C.^1,2

Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France^1

CNRS, IRAP, 9 Av. Colonel Roche, Toulouse Cedex 4

31028, France^2

Group of Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de La Cruz N3, Madrid

E-28049, Spain^3

关键词: Bottom up;    Emission features;    Formation mechanism;    Midinfrared;    Non-detection;    Planetary nebula;    Polycyclic aromatic hydrocarbon (PAH);    Small hydrocarbons;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/728/3/032011/pdf
DOI  :  10.1088/1742-6596/728/3/032011

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

This paper presents the Spitzer IRS (Infra Red Spectrograph) detection of mid-infrared polycyclic aromatic hydrocarbon (PAH) emission features and H2associated with dense knots in the ring of the "oxygen-rich" (C/O∼0.6-0.8) planetary nebula (PN) NGC6720 (Ring Nebula). We explored a further three oxygen-rich extended PNe with similar dataset available. These turned out to be non-detection of PAHs, although two of these do contain H2 emission knots. The presence of PAHs is discussed in the context of a bottom-up formation mechanism, in which first small hydrocarbons, and later PAHs, are formed in warm dense knots inside the ionised regions of PNe.