Crystalline silicates in AGB and post-AGB stars
| Autor: | Waters, LBFM, Molster, FJ, LeBertre, T, Lebre, A, Waelkens, C |
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| Přispěvatelé: | Low Energy Astrophysics (API, FNWI), University of Groningen |
| Rok vydání: | 1999 |
| Předmět: |
DUST SHELLS
NUCLEI RED-RECTANGLE MINERALOGY Astrophysics::Cosmology and Extragalactic Astrophysics BINARY WAVELENGTH SPECTROMETER CARBON STARS Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics PLANETARY-NEBULAE EMISSION SILICON Astrophysics::Galaxy Astrophysics |
| Zdroj: | Asymptotic giant branch stars, 209-219 STARTPAGE=209;ENDPAGE=219;TITLE=Asymptotic giant branch stars ASYMPTOTIC GIANT BRANCH STARS, 209-219 STARTPAGE=209;ENDPAGE=219;TITLE=ASYMPTOTIC GIANT BRANCH STARS |
| Popis: | We discuss ISO spectroscopy of oxygen-rich dust shells surrounding evolved stars. The dust that condenses in the outflows of stars on the Asymptotic Giant Branch consists mainly of amorphous silicates and simple oxides. For high mass loss rates, crystalline silicates begin to appear at modest abundance. These crystalline silicates are cold and Fe-poor. ISO spectroscopy for the first time allows quantitative mineralogy of oxygen-rich circumstellar dust. Crystalline silicates are found at high abundance in sources with peculiar (disk) geometry, such as long-lived circum-binary disks. Some C-rich post-AGB stars, notably the Red Rectangle and several nebulae surrounding [WC] central stars of Planetary Nebulae, also show crystalline silicates. We speculate on the origin and evolution of the crystalline dust component in evolved stars. |
| Databáze: | OpenAIRE |
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