ON THE ABUNDANCE ENIGMA IN IONIZED REGIONS
In ionized regions with temperature gradients and uctuations, the ratio of the ion abundance obtained from a recombination line to that found from a colli- sionally excited line (CEL), or ADF, is smaller than observed (ADF 2). Larger ADFs are found when there is an additional component that is 30% c...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:57112288009 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57112288009 |
| Access Level: | acceso abierto |
| Palabra clave: | Física, Astronomía y Matemáticas general ISM: abundances ISM: H II regions ISM: planetary nebulae |
| Sumario: | In ionized regions with temperature gradients and uctuations, the ratio of the ion abundance obtained from a recombination line to that found from a colli- sionally excited line (CEL), or ADF, is smaller than observed (ADF 2). Larger ADFs are found when there is an additional component that is 30% colder. The temperature in the cold component must be 500, 200 and 100 K if the ADF found from an IR CEL is ' 2, 5 and 10. Most of the mass is in the hot region. The total H+ mass has been underestimated if it was found from the intensity of a Balmer line. [O IIII]5007/H images can also render the relative distribution of cold and hot matter. The determination of accurate abundances is forestalled by the fact that observations cannot discriminate light from these components, the existence of distinct abundance sets and insucient spectral information for the hot region. |
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