Chandra-LETGS X-ray observation of α Centauri : A nearby (G2V + K1V) binary system
Chandra-LETGS X-ray observation of α Centauri : A nearby (G2V + K1V) binary system
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DOI：
10.1051/0004-6361:20021899
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发表时间：
2003-03
影响因子：
6.5
通讯作者：
A. Raassen;J. Ness;R. Mewe;R. Meer;V. Burwitz;J. Kaastra
中科院分区：
文献类型：
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作者：
A. Raassen;J. Ness;R. Mewe;R. Meer;V. Burwitz;J. Kaastra
钱德拉 LETGS 对半人马座 α 的 X 射线观测，曝光时间为 81.5 ks，首次对两个分量（K1V 和 G2V）进行了光谱解析。我们使用各个光谱的发射线来确定等离子体温度，并发现与太阳相似的温度，但 K1V 恒星的温度高于 G2V 恒星。使用全局拟合技术来构建每颗恒星的排放测量分布，我们发现排放测量分布与从线比中发现的一致。使用双温度模型以获得标准化为铁并相对于太阳光层值的丰度。对于两颗恒星，我们发现 FIP 效应对于 K1V 分量有轻微但不显着的更强 FIP 效应的趋势。
A Chandra LETGS X-ray observation of α Centauri with an exposure time of 81.5 ks is presented with the two components (K1V and G2V) spectrally resolved for the first time. We use the emission lines from the individual spectra to determine plasma temperatures and find similar temperatures as for the Sun with higher temperatures for the K1V star than for the G2V star. Global fitting techniques are used in order to construct an emission measure distribution for each star and we find emission measure distributions consistent with what is found from the line ratios. A two-temperature model is used in order to derive abundances normalized to iron and relative to solar photosheric values. For both stars we find a FIP effect with a slight but not significant tendency of a stronger FIP effect for the K1V component.