The chemical compositions of the extreme halo stars HE0107-5240 and HE1327-2326 inferred from 3D hydrodynamical model atmospheres

Abstract

We investigate the impact of realistic 3D hydrodynamical model stellar atmospheres on the determination of elemental abundances in the carbon-rich, hyper iron-poor stars HE0107-5240 and HE1327-2326. We derive the chemical compositions of the two stars by means of a detailed 3D analysis of spectral lines under the assumption of local thermodynamic equilibrium (LTE). The lower temperatures of the line-forming regions of the hydrodynamical models cause changes in the predicted spectral line strengths. In particular we find the 3D abundances of C, N, and O to be lower by ~ -0.8 dex (or more) than estimated from a 1D analysis. The 3D abundances of iron-peak elements are also decreased but by smaller factors (~ -0.2 dex). We caution however that the neglected non-LTE effects might actually be substantial for these metals. We finally discuss possible implications for studies of early Galactic chemical evolution.

arXiv commentAccepted for publication in ApJL

References in corpus (19)

• Stellar evolution with rotation VIII: Models at Z = 10^{-5} and CNO yields for early galactic evolution
• Nucleosynthetic signatures of the first stars
• A stellar relic from the early Milky Way
• First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
• First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
• The early star generations: the dominant effect of rotation on the CNO yields
• The first chemical enrichment in the universe and the formation of hyper metal-poor stars
• HE0107-5240, A Chemically Ancient Star.I. A Detailed Abundance Analysis
• HE1327-2326, an unevolved star with [Fe/H]<-5.0. I. A Comprehensive Abundance Analysis
• Is HE0107-5240 A Primordial Star? -- The Characteristics of Extremely Metal-Poor Carbon-Rich Stars --
• On OH line formation and oxygen abundances in metal-poor stars
• On the origin of HE0107-5240, the most iron deficient star presently known
• On the oxygen abundance of HE0107-5240
• The Oxygen Abundance of HE 1327-2326
• Effects of line-blocking on the non-LTE Fe I spectral line formation
• Models for extremely metal-poor halo stars
• Primordial Stellar Feedback and the Origin of Hyper Metal-Poor Stars
• Excavation of the first stars
• Evolution and nucleosynthesis of primordial low mass stars

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