Hierro y polvo en nebulosas planetarias
Interstellar dust plays a very important role both in the formation and evolution of stars and in the evolution of the interstellar medium. An important tool in the study of dust grains is based on the comparison between the gaseous abundances of refractory elements in the interstellar medium with a...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis de maestría |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2007 |
| País: | México |
| Institución: | Instituto Nacional de Astrofísica, Óptica y Electrónica |
| Repositorio: | Repositorio Institucional del INAOE |
| Idioma: | español |
| OAI Identifier: | oai:inaoe.repositorioinstitucional.mx:1009/593 |
| Acceso en línea: | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/593 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Nebulosas planetarias/Planetary nebulae info:eu-repo/classification/Elemento de abundancia relativa/Element relative abundance info:eu-repo/classification/Polvo/Dust info:eu-repo/classification/Hierro/Iron info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/21 info:eu-repo/classification/cti/2105 info:eu-repo/classification/cti/210502 |
| Sumario: | Interstellar dust plays a very important role both in the formation and evolution of stars and in the evolution of the interstellar medium. An important tool in the study of dust grains is based on the comparison between the gaseous abundances of refractory elements in the interstellar medium with a reference abundance, since this comparison informs us of the degree of incorporation of such elements onto dust grains. The main objective of this thesis is to constrain the Fe abundance in a sample of 18 low-ionization planetary nebulae (PNe): 13 were selected from the literature because they had all the lines we needed for the analysis, the other 5 were observed in the 2.1–m telescope at San Pedro Martir. In this sample of PNe, Fe++ and Fe+3 are the main contributors to the total abundance of iron. We determine Fe abundances from [Fe III] lines and two ionization correction factors that account for the contribution of Fe+3, one of them derived from photoionization models, and the other one calculated from observational data of objects with available measurements of [Fe III] and [Fe IV] lines. We find a very low Fe abundance in our sample of PNe, with less than 10% of their total Fe abundance present in the gas; the remaining atoms are probably condensed onto dust grains. The depletion factors we find for our PNe sample are similar to those found in H II regions. This is a relevant result since the dust present in H II regions is interstellar dust, whereas in PNe the dust was formed in the atmosphere of the progenitor star during the early stages of the formation of the PNe. |
|---|