PAH formation in O-rich planetary nebulae

@article{GuzmanRamirez2014PAHFI,
  title={PAH formation in O-rich planetary nebulae},
  author={Lizette Guzman-Ramirez and E. Lagadec and D. Jones and Albert A. Zijlstra and Krzysztof M. Gesicki},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2014},
  volume={441},
  pages={364-377}
}
Polycyclic aromatic hydrocarbons (PAHs) have been observed in O-rich planetary nebulae towards the Galactic Bulge. This combination of oxygen-rich and carbon-rich material, known as dual-dust or mixed chemistry, is not expected to be seen around such objects. We recently proposed that PAHs could be formed from the photodissociation of CO in dense tori. In this work, using VISIR/VLT, we spatially resolved the emission of the PAH bands and ionised emission from the [SIV] line, confirming the… 

Polycyclic aromatic hydrocarbons and molecular hydrogen in oxygen-rich planetary nebulae: the case of NGC 6720.

Spitzer-IRS mid-infrared spectroscopic imaging of the nearby, oxygen-rich planetary nebula NGC 6720 reveals the presence of the 11.3 μm aromatic (PAH) emission band, suggesting that the local conditions in an oxygen- rich environment can also become conducive to in-situ formation of large carbonaceous molecules, such as PAHs, via a bottom-up chemical pathway.

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