Ultra-metal-poor Stars: Spectroscopic Determination of Stellar Atmospheric Parameters Using Iron Non-LTE Line Abundances
Journal Article
·
· Astrophysical Journal
- Joint Institute for Nuclear Astrophysics, Center for the Evolution of the Elements, East Lansing, MI 48824 (United States)
- Laboratoire Univers et Particules de Montpellier, Université de Montpellier, CNRS, UMR 5299, Montpellier (France)
We present new ultra-metal-poor stars parameters with [Fe/H] < −4.0 based on line-by-line non-local thermodynamic equilibrium (NLTE) abundances using an up-to-date iron model atom with a new recipe for non-elastic hydrogen collision rates. We study the departures from LTE in their atmospheric parameters and show that they can grow up to ∼1.00 dex in [Fe/H], ∼150 K in T{sub eff} and ∼0.5 dex in log g toward the lowest metallicities. Accurate NLTE atmospheric stellar parameters, in particular [Fe/H] being significantly higher, are the first step to eventually providing full NLTE abundance patterns that can be compared with Population III supernova nucleosynthesis yields to derive properties of the first stars. Overall, this maximizes the potential of these likely second-generation stars to investigate the early universe and how the chemical elements were formed.
- OSTI ID:
- 22875734
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 847; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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