C I non-LTE spectral line formation in late-type stars

D. Fabbian; M. Asplund; M. Carlsson; D. Kiselman

doi:10.1017/S1743921305005703

C I non-LTE spectral line formation in late-type stars

D. Fabbian^*, M. Asplund, M. Carlsson, D. Kiselman

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations suggest that the carbon non-LTE corrections in these stars are higher than usually adopted, remaining substantial even at low metallicity. For the most metal-poor stars in the sample of Akerman et al. (2004), the effects are of the order of Δ log ε_C ≃ -0.35... -0.45 (when neglecting H collisions). Applying our results to those observations, the apparent [C/O] upturn seen in their LTE analysis is no longer present, thus revealing no need to invoke contributions from Pop. III stars to the carbon nucleosynthesis.

Original language	English
Pages (from-to)	255-256
Number of pages	2
Journal	Proceedings of the International Astronomical Union
Volume	1
Issue number	S228
DOIs	https://doi.org/10.1017/S1743921305005703
Publication status	Published - 2005

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title = "C I non-LTE spectral line formation in late-type stars",

abstract = "We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations suggest that the carbon non-LTE corrections in these stars are higher than usually adopted, remaining substantial even at low metallicity. For the most metal-poor stars in the sample of Akerman et al. (2004), the effects are of the order of Δ log εC ≃ -0.35... -0.45 (when neglecting H collisions). Applying our results to those observations, the apparent [C/O] upturn seen in their LTE analysis is no longer present, thus revealing no need to invoke contributions from Pop. III stars to the carbon nucleosynthesis.",

keywords = "Atmospheres, Line: formation, Radiative transfer - stars: abundances",

author = "D. Fabbian and M. Asplund and M. Carlsson and D. Kiselman",

year = "2005",

doi = "10.1017/S1743921305005703",

language = "English",

volume = "1",

pages = "255--256",

journal = "Proceedings of the International Astronomical Union",

issn = "1743-9213",

publisher = "Cambridge University Press",

number = "S228",

}

TY - JOUR

T1 - C I non-LTE spectral line formation in late-type stars

AU - Fabbian, D.

AU - Asplund, M.

AU - Carlsson, M.

AU - Kiselman, D.

PY - 2005

Y1 - 2005

N2 - We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations suggest that the carbon non-LTE corrections in these stars are higher than usually adopted, remaining substantial even at low metallicity. For the most metal-poor stars in the sample of Akerman et al. (2004), the effects are of the order of Δ log εC ≃ -0.35... -0.45 (when neglecting H collisions). Applying our results to those observations, the apparent [C/O] upturn seen in their LTE analysis is no longer present, thus revealing no need to invoke contributions from Pop. III stars to the carbon nucleosynthesis.

AB - We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations suggest that the carbon non-LTE corrections in these stars are higher than usually adopted, remaining substantial even at low metallicity. For the most metal-poor stars in the sample of Akerman et al. (2004), the effects are of the order of Δ log εC ≃ -0.35... -0.45 (when neglecting H collisions). Applying our results to those observations, the apparent [C/O] upturn seen in their LTE analysis is no longer present, thus revealing no need to invoke contributions from Pop. III stars to the carbon nucleosynthesis.

KW - Atmospheres

KW - Line: formation

KW - Radiative transfer - stars: abundances

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U2 - 10.1017/S1743921305005703

DO - 10.1017/S1743921305005703

M3 - Article

AN - SCOPUS:63549144485

SN - 1743-9213

VL - 1

SP - 255

EP - 256

JO - Proceedings of the International Astronomical Union

JF - Proceedings of the International Astronomical Union

IS - S228

ER -

C I non-LTE spectral line formation in late-type stars

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