A study of coronal abundances in RS CVn binaries
A study of coronal abundances in RS CVn binaries
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DOI：
10.1051/0004-6361:20021737
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发表时间：
2003-02-01
影响因子：
6.5
通讯作者：
Mewe, R
中科院分区：
文献类型：
--
作者：
Audard, M;Güdel, M;Mewe, R
我们给出了几个RS CVn双星系统的XMM-牛顿数据。用反射光栅谱仪获得的高分辨率X射线光谱已与欧洲光子成像相机光谱同时进行了解释。与高第一电离电离势(FIP)元素相比，高活动恒星显示出低第一电离电离势(FIP)的元素枯竭，而中等活动双星要么没有FIP偏向，要么可能存在类似太阳的FIP效应。我们发现，低FIP丰度与氧的比值随着日冕平均温度的变化而变化，而高FIP元素的比值保持不变。由于我们观察到Fe(Low-FIP)的绝对丰度随着活动的降低而增加，这表明低FIP的元素丰度随日冕活动水平的不同而不同。与实验室测量的FeXvii波长15.01和15.26埃谱线的强度比相比，日冕等离子体处于光学薄区。
We present XMM-Newton data of several RS CVn binary systems. High-resolution X-ray spectra obtained with the Reflection Grating Spectrometers have been interpreted simultaneously with the European Photon Imaging Camera spectra. Highly active stars show a depletion of elements with a low first ionization potential (FIP) relative to high-FIP elements, whereas intermediately active binaries show either no FIP bias or a possible solar-like FIP effect. We find that the low-FIP abundance ratios to oxygen vary with the coronal average temperature whereas the ratios for high-FIP elements stay constant. Since we observe that the absolute Fe (low-FIP) abundance increases with decreasing activity, this suggests that the abundances of elements with low FIP vary with the coronal activity level. Compared with laboratory measurements of the intensity ratios of the Fe XVII lambdalambda15.01 and 15.26 Angstrom lines, the coronal plasmas are in the optically thin regime.