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arXiv 0909.2310astro-ph.SR
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太阳粒化中的氧线。II。中心-边缘变化、NLTE谱线形成、混合和太阳氧丰度

Oxygen lines in solar granulation. II. Centre-to-limb variation, NLTE line formation, blends and the solar oxygen abundance

Tiago M. D. Pereira, Martin Asplund, Dan Kiselman

摘要:

背景:关于太阳氧丰度和3D模型在最近向下修订中的作用有一场激烈的辩论。这些模型已经用高分辨率的太阳地图集进行了测试。进一步的测试可以使用中心到肢体的变化来完成。目的:使用高质量的观测整个太阳表面的氧线,我们试图测试,如果3D和1D模型再现其所观察到的中心到边缘的变化(CLV)。特别是,我们试图评估是否三维模型是适当的,以获得太阳氧丰度。研究方法:利用我们最近对OI 777 nm、OI615.81nm、[OI] 630.03nm和其他元素的9条谱线的观测结果,对宁静日面的5个视角(0.2我们将它们与使用最新的线路形成代码,线路数据和允许LTE偏离计算的3D和1D模型的预测线路轮廓进行比较。OI 777 nm谱线的CLV也被用于获得对与H的非弹性碰撞的知之甚少的效率的经验校正。结果:3D模型通常很好地再现了管线的CLV观察结果,特别是氧气管线。从OI 777 nm线,我们发现,经典的Drawin配方稍微高估了H碰撞。OI 615.82 nm谱线的临边观测使我们能够确定这条谱线的分子的一个以前未知的贡献,在太阳临边普遍存在。[OI] 630.03 nm谱线的详细处理表明,3D建模与观测结果非常吻合。用三维模型导出的氧丰度分别为8.68(OI 777 nm)、8.66([OI] 630.03 nm)和8.62(OI 615.82 nm)。结论:这些额外的测试加强了丰度分析的3D模型和线条形成的可信度。

英文摘要:

Context: There is a lively debate about the solar oxygen abundance and the role of 3D models in its recent downward revision. The models have been tested using high resolution solar atlases. Further testing can be done using centre-to-limb variations. Aims: Using high quality observations of oxygen lines across the solar surface we seek to test if the 3D and 1D models reproduce their observed centre-to-limb variation (CLV). In particular we seek to assess whether the 3D model is appropriate to derive the solar oxygen abundance. Methods: We use our recent observations of OI 777 nm, OI 615.81 nm, [OI] 630.03 nm and nine lines of other elements for five viewing angles 0.2<mu<1 of the quiet solar disk. We compare them with the predicted line profiles from the 3D and 1D models computed using the most up-to-date line formation codes, line data and allowing for departures of LTE. The CLV of the OI 777 nm lines is also used to obtain an empirical correction for the poorly known efficiency of the inelastic collisions with H. Results: The 3D model generally reproduces the CLV observations of the lines very well, particularly the oxygen lines. From the OI 777 nm lines we find that the classical Drawin recipe slightly overestimates H collisions. The limb observations of the OI 615.82 nm line allow us to identify a previously unknown contribution of molecules for this line, prevalent at the solar limb. A detailed treatment of the [OI] 630.03 nm line shows that the 3D modeling provides an excellent agreement with the observations. The derived oxygen abundances with the 3D model are 8.68 (OI 777 nm), 8.66 ([OI] 630.03 nm) and 8.62 (OI 615.82 nm). Conclusions: These additional tests have reinforced the trustworthiness of the 3D model and line formation for abundance analyses.

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