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M. E. Kress (San Jose State University), A.G.G.M. Tielens (Kapteyn Astronomical Institute), M.E. Frenklach (University of California, Berkeley)
Polycyclic aromatic hydrocarbons (PAHs) are one of the predominant carriers of carbon in interstellar space, after CO. PAHs are also observed in circumstellar environments (e.g. GL 618 and the Red Rectangle). The presence of PAHs in stellar outflows, in the ISM and in meteorites raise several important questions: are meteoritic PAHs inherited from late-type stars? Are these compounds modified in the solar nebula, and if so, how, where and when? Can the abundances and varieties of PAHs in stellar outflows give more insight into the evolution of stars off the main sequence through the planetary nebula stage? To this end, we are modeling the chemical kinetics of PAH formation, growth and destruction within a parameter space of outflow timescales, pressures, temperatures, C/O ratios and other factors to address these questions. The chemical kinetics of PAHs has been well studied at the higher temperatures of plug flow reactors and sooting flames (> 1000 K), and we base our chemical model upon these studies. We hope that our results will motivate more detailed experimental studies of PAH chemistry at the lower temperatures and pressures characteristic of circumstellar environments. This work has been supported by NASA Astrobiology Institute's Virtual Planetary Laboratory and the Institute for Geophysics and Planetary Physics at Lawrence Livermore National Laboratory.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.