High-resolution Keck I spectroscopy of Galactic halo post-asymptotic giant branch stars
Data(s) |
11/12/2002
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Resumo |
Absolute and differential abundance analyses have been performed from high-resolution, high signal-to-noise ratio optical (Keck I) spectra for three evolved Galactic halo stars, namely PG 1704 + 222, HD 341617 and LSIV -0401. Their derived atmospheric parameters indicate that all three objects are undergoing a post-asymptotic giant branch (post-AGB) phase of evolution. A differential abundance analysis reveals HD 341617 as having a mild carbon deficiency of 0.74 dex, possibly due to the star having evolved off the AGB before the onset of the third dredge-up. Although such carbon underabundances are typical of hot post-AGB objects, the same trend is not observed in PG 1704 + 222, where the carbon abundance is found to be consistent with those derived for nitrogen and oxygen. Hence, a dredge-up scenario need not be invoked to explain the chemical composition of PG 1704 + 222. For LSIV -0401 no iron deficiency is apparent relative to magnesium and silicon, and hence a gas- dust separation event in the AGB progenitor need not be invoked for this star. |
Identificador |
http://dx.doi.org/10.1046/j.1365-8711.2002.05912.x http://www.scopus.com/inward/record.url?scp=0013016921&partnerID=8YFLogxK |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Mooney , C J , Rolleston , W R J , Keenan , F , Dufton , P , Smoker , J , Ryans , R & Aller , J H 2002 , ' High-resolution Keck I spectroscopy of Galactic halo post-asymptotic giant branch stars ' Monthly Notices of the Royal Astronomical Society , vol 337 , no. 3 , pp. 851-860 . DOI: 10.1046/j.1365-8711.2002.05912.x |
Palavras-Chave | #/dk/atira/pure/subjectarea/asjc/1900/1912 #Space and Planetary Science |
Tipo |
article |