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The temperature scale of metal-poor dwarfs: lithium and oxygen abundances

Published online by Cambridge University Press:  23 December 2005

Jorge Meléndez ,
Nataliya G. Shchukina ,
Iván Ramírez  and
Irina Vasiljeva
Jorge Meléndez
Affiliation:
Department of Astronomy, Caltech, 1200 E. California Blvd, Pasadena, CA 91125 email: [email protected]
Nataliya G. Shchukina
Affiliation:
Main Astronomical Observatory, National Academy of Sciences, 27 Zabolotnogo Street, Kiev 03680, Ukraine
Iván Ramírez
Affiliation:
Department of Astronomy, University of Texas at Austin, RLM 15.306, TX 78712
Irina Vasiljeva
Affiliation:
Main Astronomical Observatory, National Academy of Sciences, 27 Zabolotnogo Street, Kiev 03680, Ukraine
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Abstract

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We employ a new Infrared Flux Method (IRFM) temperature scale (Ramírez & Meléndez 2005a, b) in order to determine Li, O, and Fe NLTE abundances in a sample of relatively unevolved (dwarfs, turn-off, subgiants) metal-poor stars. We show that the analysis of the permitted OI triplet and FeII lines leads to a plateau in [OI/FeII] over the broad metallicity range $-3.2 <$ [Fe/H] $<-$0.7, independent of temperature and metallicity, and with a star-to-star scatter of only 0.1 dex. The Li abundance in halo stars is also found to be independent of temperature and metallicity (Spite plateau), with a star-to-star scatter of just 0.06 dex over the metallicity range $-3.4 <$ [Fe/H] $<-1$. Our Li abundance (Meléndez & Ramírez 2004) is higher than previously reported values, but still lower than the primordial abundance suggested by WMAP data and BBN.

Keywords

Stars: fundamental parametersstars: abundancesstars: halo
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 1 , Symposium S228: From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution , May 2005 , pp. 265 - 266
Copyright
© 2005 International Astronomical Union