文章基本信息

标题：Observational constraints on the origin of the elements
其他标题：II. 3D non-LTE formation of Ba IIlines in the solar atmosphere
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作者：A. J. Gallagher ; M. Bergemann ; R. Collet 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：634
页码：1-11
DOI：10.1051/0004-6361/201936104
语种：English
出版社：EDP Sciences
摘要：Context.The pursuit of more realistic spectroscopic modelling and consistent abundances has led us to begin a new series of papers designed to improve current solar and stellar abundances of various atomic species. To achieve this, we have begun updating the three-dimensional (3D) non-local thermodynamic equilibrium (non-LTE) radiative transfer code, MULTI3D, and the equivalent one-dimensional (1D) non-LTE radiative transfer code, MULTI 2.3.Aims.We examine our improvements to these codes by redetermining the solar barium abundance. Barium was chosen for this test as it is an important diagnostic element of thes-process in the context of galactic chemical evolution. New Ba II+ H collisional data for excitation and charge exchange reactions computed from first principles had recently become available and were included in the model atom. The atom also includes the effects of isotopic line shifts and hyperfine splitting.Methods.A grid of 1D LTE barium lines were constructed with MULTI 2.3 and fit to the four Ba IIlines available to us in the optical region of the solar spectrum. Abundance corrections were then determined in 1D non-LTE, 3D LTE, and 3D non-LTE. A new 3D non-LTE solar barium abundance was computed from these corrections.Results.We present for the first time the full 3D non-LTE barium abundance ofA(Ba) = 2.27 ± 0.02 ± 0.01, which was derived from four individual fully consistent barium lines. Errors here represent the systematic and random errors, respectively.
关键词：Key wordsenhydrodynamicsradiative transferline: formation