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Autre Publication Scientifique Année : 2011

Can PAH clusters survive in PDRs?

J. Montillaud
  • Fonction : Auteur
Aude Simon
P. Parneix
  • Fonction : Auteur

Résumé

Astronomical observations reveal an active chemistry of the carbonaceous species in photodissociation regions (PDRs), involving polycyclic aromatic hydrocarbons (PAHs) and very small carbonaceous grains. Recent analysis of mid-IR observations (Pilleri et al., submitted) support the evolutionary scenario proposed by Rapacioli et al. (2005, A&A) in which free PAHs are produced by evaporation of very small carbonaceous grains. These authors also proposed PAH clusters as models for these grains and tested this hypothesis for the specific case of coronene (C24H12) clusters (Rapacioli et al. 2006, A&A). They concluded that even though the formation of PAH clusters by collision of PAHs is efficient in PDRs, their destruction by UV photons is much faster. However, astrophysical PAHs are thought to be much larger than coronene and the stability of PAH clusters is expected to increase with the size of PAH units. We revisited this work and considered the photoevaporation of circumcoronene (C54H18) clusters. Our results lay on -(i)- molecular dynamic simulations and phase space theory to describe molecular properties and -(ii)- an astrochemical model using rate equations. We conclude about the ability of PAH clusters to survive in PDRs.
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Dates et versions

hal-00843470 , version 1 (11-07-2013)

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J. Montillaud, Christine Joblin, D. Toublanc, Aude Simon, P. Parneix. Can PAH clusters survive in PDRs?. 2011, pp.Poster57. ⟨hal-00843470⟩
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