CI non LTE spectral line formation in late-type stars

Fabbian, D.; Asplund, M.; Carlsson, M.; Kiselman, D.
Referencia bibliográfica

From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution, IAU Symposium Proceedings of the international Astronomical Union 228, Held in Paris, France, May 23-27, 2005. edited by Hill, V.; François, P.; Primas, F. Cambridge: Cambridge University Press, 2005., pp.255-256

Fecha de publicación:
0
2005
Número de autores
4
Número de autores del IAC
0
Número de citas
3
Número de citas referidas
3
Descripción
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 ΔlogɛC ≃ -0.35ldots-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.