Excitation of emission lines by fluorescence and recombination in IC 418
| Autor: | Vladimir Escalante, L. Georgiev, Christophe Morisset |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Physics
Nebula FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Computer Science::Computational Geometry Photodissociation region Fluorescence Astrophysics - Astrophysics of Galaxies Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Electron excitation Astrophysics of Galaxies (astro-ph.GA) Excited state Astrophysics::Solar and Stellar Astrophysics Emission spectrum Atomic physics Forbidden mechanism Solar and Stellar Astrophysics (astro-ph.SR) Excitation Astrophysics::Galaxy Astrophysics |
| Zdroj: | NASA Astrophysics Data System |
| Popis: | We predict intensities of lines of CII, NI, NII, OI and OII and compare them with a deep spectroscopic survey of IC 418 to test the effect of excitation of nebular emission lines by continuum fluorescence of starlight. Our calculations use a nebular model and a synthetic spectrum of its central star to take into account excitation of the lines by continuum fluorescence and recombination. The NII spectrum is mostly produced by fluorescence due to the low excitation conditions of the nebula, but many CII and OII lines have more excitation by fluorescence than recombination. In the neutral envelope, the NI permitted lines are excited by fluorescence, and almost all the OI lines are excited by recombination. Electron excitation produces the forbidden optical lines of OI, but continuum fluorescence excites most of the NI forbidden line intensities. Lines excited by fluorescence of light below the Lyman limit thus suggest a new diagnostic to explore the photodissociation region of a nebula. 2 pages, 4 figures, to appear in proceedings of the IAU Symposium 283: "Planetary Nebulae: An Eye to the Future", Eds.: A. Manchado, L. Stanghellini and D. Schoenberner |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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