A non-LTE abundance analysis of the post-AGB star ROA 5701
| Autor: | Robert Ryans, Francis P. Keenan, Philip Dufton, J. V. Smoker, H. M. A. Thompson |
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| Rok vydání: | 2006 |
| Předmět: |
Physics
Thermodynamic equilibrium Metallicity Astrophysics (astro-ph) Astrophysics::Instrumentation and Methods for Astrophysics FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Omega Stars Space and Planetary Science Abundance (ecology) Globular cluster Astrophysics::Solar and Stellar Astrophysics Asymptotic giant branch Astrophysics::Earth and Planetary Astrophysics Spectrograph Astrophysics::Galaxy Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 368:1749-1756 |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1111/j.1365-2966.2006.10257.x |
| Popis: | An analysis of high-resolution Anglo-Australian Telescope (AAT)/ University College London Echelle Spectrograph (UCLES) optical spectra for the ultraviolet (UV)-bright star ROA 5701 in the globular cluster omega Cen (NGC 5139) is performed, using non-local thermodynamic equilibrium (non-LTE) model atmospheres to estimate stellar atmospheric parameters and chemical composition. Abundances are derived for C, N, O, Mg, Si and S, and compared with those found previously by Moehler et al. We find a general metal underabundance relative to young B-type stars, consistent with the average metallicity of the cluster. Our results indicate that ROA 5701 has not undergone a gas-dust separation scenario as previously suggested. However, its abundance pattern does imply that ROA 5701 has evolved off the AGB prior to the onset of the third dredge-up. Comment: 9 pages, 2 figures. Accepted for publication in MNRAS (Online Early) |
| Databáze: | OpenAIRE |
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