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ABUNDANCE; DWARF STARS; SPECTRUM ANALYSIS; STELLAR ATMOSPHERES; STELLAR MODELS; STELLAR SPECTROPHOTOMETRY; IRON; LINE SPECTRA; SOLAR SPECTRA; SPECTRAL LINE WIDTH; STELLAR EVOLUTION; STELLAR MASS; STELLAR TEMPERATURE; SUBGIANT STARS
Abstract :
[en] High resolution spectrophotometric data were obtained for the stellar objects HD 19445 and HD 140283. The spectra gathered were well-matched by model stellar atmospheres for the continuous flux and Fe I excitation equilibrium. HD 19445 was identified as a dwarf star and HD 140283 as a subgiant. Abundance analyses indicated an Fe abundance lower than previously estimated, oxygen overabundant relative to C and Fe, Mg, Si and Ca overabundant relative to Fe, and deficiencies of Al and Mn. Sr was overabundant relative to Ba. The abundance discrepancies are in disagreement with the standard nucleosynthesis model. Further such spectroscopic data are needed to develop accurate galactic chemical evolution models.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Magain, Pierre ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Language :
English
Title :
Spectroscopic analysis of extreme metal-poor 'dwarfs'. II - Improved model atmospheres and detailed abundances