The iron abundance in galactic planetary nebulae ⃰
We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors that take into account uncertainties in the atomic data. We find very low iron abu...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2009 |
| País: | México |
| Institución: | Instituto Nacional de Astrofísica, Óptica y Electrónica |
| Repositorio: | Repositorio Institucional del INAOE |
| Idioma: | inglés |
| OAI Identifier: | oai:inaoe.repositorioinstitucional.mx:1009/1367 |
| Acceso en línea: | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/1367 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Inspec/Planetary nebulae: general info:eu-repo/classification/Inspec/ISM: abundances info:eu-repo/classification/Inspec/Dust, extinction info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/21 |
| Sumario: | We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors that take into account uncertainties in the atomic data. We find very low iron abundances in all the objects, suggesting that more than 90% of their iron atoms are condensed onto dust grains. This number is based on the solar iron abundance and implies a lower limit on the dust-to-gas mass ratio, solely due to iron, of Mdust/Mgas ≥ 1.3 × 10⁻³ for our sample. The depletion factors of different PNe cover about two orders of magnitude, probably reflecting differences in the formation, growth, or destruction of their dust grains. However, we do not find any systematic difference between the gaseous iron abundances calculated for C-rich and O-rich PNe, suggesting similar iron depletion efficiencies in both environments. The iron abundances of our sample PNe are similar to those derived following the same procedure for a group of 10 Galactic H II regions. These high depletion factors argue for high depletion efficiencies of refractory elements onto dust grains both in molecular clouds and asymptotic giant brach stars, and low dust destruction efficiencies both in interstellar and circumstellar ionized gas. |
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