PAH formation in O-rich planetary nebulae

  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},
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.

Molecular studies of Planetary Nebulae

  • Yong Zhang
  • Physics
    Proceedings of the International Astronomical Union
  • 2016
Abstract Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN),

PAH and H2 emission in the Ring Nebula

This paper presents the Spitzer IRS (Infra Red Spectrograph) detection of mid-infrared polycyclic aromatic hydrocarbon (PAH) emission features and H2 associated with dense knots in the ring of the

Dust in planetary nebulae

  • G. Sloan
  • Physics
    Proceedings of the International Astronomical Union
  • 2016
Abstract Infrared spectra from the Spitzer Space Telescope trace the evolution of carbon-rich dust from the asymptotic giant branch (AGB) to young planetary nebulae (PNe). On the AGB, amorphous


Hydrocarbon organic material, as found in the interstellar medium, exists in complex mixtures of aromatic and aliphatic forms. It is considered to originate from carbon-enriched giant stars during

A Review in Mixed Chemistry of Low Mass Evolved Stars

During the late stages of their evolution, Sun-like stars bring the products of nuclear burning to the surface. Although there is a chemical dichotomy between oxygen-rich and carbon-rich evolved

Destruction and multiple ionization of PAHs by X-rays in circumnuclear regions of AGNs

The infrared signatures of polycyclic aromatic hydrocarbons (PAHs) are observed in a variety of astrophysical objects, including the circumnuclear medium of active galactic nuclei (AGNs). These are

Witnessing the emergence of a carbon star

During the late stages of their evolution, Sun-like stars bring the products of nuclear burning to the surface. Most of the carbon in the Universe is believed to originate from stars with masses up

The planetary nebula IC 4776 and its post-common-envelope binary central star

We present a detailed analysis of IC 4776, a planetary nebula displaying a morphology believed to be typical of central star binarity. The nebula is shown to comprise a compact hourglass-shaped

The Herschel Planetary Nebula Survey (HerPlaNS): A Comprehensive Dusty Photoionization Model of NGC6781

Through iterative fitting using the Cloudy code with empirically derived constraints, this work finds the best-fit dusty photoionization model of the object that would inclusively reproduce all of the adopted panchromatic observational data.



Carbon chemistry in Galactic bulge planetary nebulae

Galactic bulge planetary nebulae show evidence of mixed chemistry with emission from both silicate dust and polycyclic aromatic hydrocarbons (PAHs). This mixed chemistry is unlikely to be related to

An oxygen-rich dust disk surrounding an evolved star in the Red Rectangle

The Red Rectangle is the prototype of a class of carbon-rich reflection nebulae surrounding low-mass stars in the final stages of evolution. The central star of this nebula has ejected most of its

The mixed chemistry phenomenon in Galactic Bulge PNe

Aims. We investigate the dual-dust chemistry phenomenon in planetary nebulae (PNe) and discuss reasons for its occurrence, by analyzing Spitzer/IRS spectra of a sample of 40 Galactic PNe among which

Molecular chemistry and the missing mass problem in planetary nebulae

Context. Detections of molecular lines, mainly from H2 and CO, reveal molecular material in planetary nebulae. Observations of a variety of molecules suggest that the molecular composition in these

The dual dust chemistries of planetary nebulae with [WCL] central stars

The rather rare class of central stars of planetary nebulae that show very low-excitation Wolf-Rayet spectra has been a subject of great interest, particularly in the infrared, since its discovery in

Chemical Abundances and Dust in Planetary Nebulae in the Galactic Bulge

We present mid-infrared Spitzer spectra of 11 planetary nebulae in the Galactic bulge. We derive argon, neon, sulfur, and oxygen abundances for them using mainly infrared line fluxes combined with

Chemistry and clumpiness in planetary nebulae

We study the chemistry in the slow wind during the transition from asymptotic giant branch (AGB) star to protoplanetary nebula (PPN) and planetary nebula (PN). We show that there is a very rich

Water Ice, Silicate, and Polycyclic Aromatic Hydrocarbon Emission Featuresin the Infrared Space Observatory Spectrum of the Carbon-richPlanetary Nebula CPD –56°8032

Combined Infrared Space Observatory Short-Wavelength Spectrometer and Long-Wavelength Spectrometer spectroscopy is presented of the late WC-type planetary nebula nucleus CPD -56°8032 and its

Planetary nebulae with emission-line central stars

Received ; accepted Abstract. The kinematic structure of a sample of planetary nebulae, consisting of 23 (WR) central stars, 21 weak emission line stars (wels) and 57 non-emission line central stars,

A study of the kinematics and binary-induced shaping of the planetary nebula HaTr 4

We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula HaTr 4, one of few known to contain a post-common-envelope central star system. Common-envelope