A Differential Abundance Analysis of Very Metal-poor Stars* †

  • O’Malley E
  • McWilliam A
  • Chaboyer B
  • et al.
7Citations
Citations of this article
7Readers
Mendeley users who have this article in their library.

Abstract

We have performed a differential line-by-line chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main-sequence (MS) halo stars, near [Fe/H] = −2 dex. Our abundances range from dex with conservative uncertainties of 0.07 dex. We find an average [ α /Fe] = 0.34 ± 0.09 dex, typical of the Milky Way. While our spectroscopic atmosphere parameters provide good agreement with Hubble Space Telescope parallaxes, there is significant disagreement with temperature and gravity parameters indicated by observed colors and theoretical isochrones. Although a systematic underestimate of the stellar temperature by a few hundred degrees could explain this difference, it is not supported by current effective temperature studies and would create large uncertainties in the abundance determinations. Both 1D and hydrodynamical models combined with separate 1D non-LTE effects do not yet account for the atmospheres of real metal-poor MS stars, but a fully 3D non-LTE treatment may be able to explain the ionization imbalance found in this work.

Cite

CITATION STYLE

APA

O’Malley, E. M., McWilliam, A., Chaboyer, B., & Thompson, I. (2017). A Differential Abundance Analysis of Very Metal-poor Stars* †. The Astrophysical Journal, 838(2), 90. https://doi.org/10.3847/1538-4357/aa62a2

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free