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Effects of Photospheric Temperature Inhomogeneities on Lithium abundance Determinations (2D)

Published online by Cambridge University Press:  25 May 2016

Roger Cayrel  and
Matthias Steffen
Roger Cayrel
Affiliation:
Observatoire de Paris, DASGAL, 61, Observatoire de Paris F75014 Paris, France
Matthias Steffen
Affiliation:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16 D-14482 Potsdam, Germany

Abstract

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Based on detailed 2D radiation hydrodynamics (RHD) simulations, we have investigated the effects of photospheric temperature inhomogeneities induced by convection on spectroscopic determinations of the lithium abundance. Computations have been performed both for the solar case and for a metal-poor dwarf. NLTE effects are taken into account, using a five-level atomic model for Li I. Comparisons are presented with traditional 1D models having the same effective temperature and gravity. The net result is that, while LTE results differ dramatically between 1D and 2D models, especially in the metal-poor case, this does not remain true when NLTE effects are included: 1D/2D differences in the inferred NLTE Li abundance are always well below 0.1 dex. The present computations still assume LTE in the continuum. New computations removing this assumption are planned for the near future.

Type
6. Stellar Knowledge to and from Light Elements
Information
Symposium - International Astronomical Union , Volume 198: The Light Elements and their Evolution , 2000 , pp. 437 - 447
Copyright
Copyright © Astronomical Society of the Pacific 2000 

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