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arXiv 0909.1210astro-ph.SR
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在BaII 4554 A谱线上观测到的从光球层到低色球层的太阳粒化

Solar granulation from photosphere to low chromosphere observed in BaII 4554 A line

R. Kostik, E. Khomenko, N. Shchukina

摘要:

本文的目的是描述650公里范围内光球层和低色球层中太阳颗粒的统计特性。我们利用在Ball 4554 A中观测到的不同大气高度上的速度和强度变化。这些观测是在特内里费岛泰德天文台的VTT观测条件良好的情况下进行的。线芯在大气中形成相当高的高度,并允许在类似研究中之前未访问的高度研究造粒特性。此外,我们分析了合成的配置文件的BaII 4554 A线计算考虑到NLTE效应的三维流体动力学模式大气中的相同的方法。我们建议一个16列模型的太阳颗粒取决于运动的方向和强度对比度测量的连续和在最上层。我们计算了强度对比度符号反转和速度符号反转的高度。我们发现,这两个参数强烈依赖于颗粒化的速度和强度在底部光球。这两个参数越大,在大气中发生的反转越高。平均而言,这种情况发生在大约200-300公里处。我们认为,这个数字也取决于线的深度的谱线在观察中使用。尽管强度和速度逆转,约40%的柱状结构的颗粒被保存到约650公里的高度。

英文摘要:

The purpose of this paper is to characterize the statistical properties of solar granulation in the photosphere and low chromosphere up to 650 km. We use velocity and intensity variations obtained at different atmospheric heights from observations in BaII 4554 A. The observations were done during good seeing conditions at the VTT at the Observatorio del Teide on Tenerife. The line core forms rather high in the atmosphere and allows granulation properties to be studied at heights that have been not accessed before in similar studies. In addition, we analyze the synthetic profiles of the BaII 4554 A line by the same method computed taking NLTE effects into account in the 3D hydrodynamical model atmosphere. We suggest a 16-column model of solar granulation depending on the direction of motion and on the intensity contrast measured in the continuum and in the uppermost layer. We calculate the heights of intensity contrast sign reversal and velocity sign reversal. We show that both parameters depend strongly on the granulation velocity and intensity at the bottom photosphere. The larger the two parameters, the higher the reversal takes place in the atmosphere. On average, this happens at about 200-300 km. We suggest that this number also depends on the line depth of the spectral line used in observations. Despite the intensity and velocity reversal, about 40% of the column structure of granulation is preserved up to heights around 650 km.

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