Some techniques developed to reproduce solar irradiance variations make use of synthetic radiative fluxes of quiet and magnetic features. The synthesis of radiative fluxes of astronomical objects is likely to be affected by uncertainties resulting from approximations and specific input employed for the synthesis. In this work we compare spectra obtained with three radiative transfer codes with the purpose of investigating differences in reproducing solar irradiance variations. Specifically, we compare spectral synthesis produced in non-local thermodynamic equilibrium obtained with COSI and RH using 1-D atmosphere models. We also compare local thermodynamic equilibrium syntheses emerging from 3-D MURaM simulations of the solar atmosphere obtained with two sets of opacity tables generated with the ATLAS9 package and with the RH code, and test the effects of opacity sampling on the emergent spectra. We find that, although the different codes and methodologies employed to synthesize the spectrum reproduce overall the observed solar spectrum with a similar degree of accuracy, subtle differences in quiet Sun spectra may translate into larger differences in the computation of the contrasts of magnetic features, which, in turn, critically affect the estimates of solar variability.

中文翻译：

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比较太阳辐照度重建的辐射转移代码和不透明度采样

为重现太阳辐照度变化而开发的一些技术利用了具有安静和磁性特征的合成辐射通量。天文物体辐射通量的合成很可能受到合成所采用的近似值和特定输入所产生的不确定性的影响。在这项工作中，我们比较了使用三种辐射传输代码获得的光谱，目的是研究再现太阳辐照度变化的差异。具体来说，我们使用一维大气模型比较了在 COSI 和 RH 获得的非局部热力学平衡中产生的光谱合成。我们还比较了使用 ATLAS9 包和 RH 代码生成的两组不透明度表获得的太阳大气 3-D MURaM 模拟中出现的局部热力学平衡合成，并测试不透明度采样对涌现光谱的影响。我们发现，虽然用于合成光谱的不同代码和方法以相似的准确度再现了整个观测到的太阳光谱，但安静太阳光谱的细微差异可能会转化为计算磁特征对比度的更大差异，这，反过来，严重影响太阳变化的估计。