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The Chemical Compos...
The Chemical Compositions of the Extreme Halo Stars HE 0107-5240 and HE 1327-2326 Inferred from Three-dimensional Hydrodynamical Model Atmospheres
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- Collet, Remo (författare)
- Uppsala universitet,Institutionen för astronomi och rymdfysik,Astronomiska observatoriet,Teoretisk astrofysik
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Asplund, Martin (författare)
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Trampedach, Regner (författare)
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(creator_code:org_t)
- 2006
- 2006
- Engelska.
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Ingår i: Astrophysical Journal. - 0004-637X. ; 664:2, s. L121-L124
- Relaterad länk:
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https://urn.kb.se/re...
Abstract
Ämnesord
Stäng
- We investigate the impact of realistic three-dimensional (3D) hydrodynamical model stellar atmospheres on the determination of elemental abundances in the carbon-rich, hyper-iron-poor stars HE 0107-5240 and HE 1327-2326. 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 about -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 (about -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.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- Astronomy
- Astronomi
Publikations- och innehållstyp
- pop (ämneskategori)
- art (ämneskategori)
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