Anomalous Fe II spectral effects and high H I Lyα temperature in gas blobs near η Carinae
Anomalous Fe II spectral effects and high H I Lyα temperature in gas blobs near η Carinae
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η Carinae 附近气体团中的异常 Fe II 光谱效应和高 H I Lyα 温度
DOI：
10.1134/1.1647477
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
V. Letokhov
中科院分区：
文献类型：
--
作者：
S. Johansson;V. Letokhov
我们考虑了在高空间分辨率和光谱分辨率下观测到的来自船底座η附近的气体团（GB）的Fe II λλ2507/2509紫外线的异常高强度的起源。这种在恒星光谱中罕见的效应可归因于几个因素的组合：（1）高氢密度（> 108 cm-3），确保了莱曼连续谱被GBs阻断，并相应地形成了完全电离的Fe原子的冷H I区;（2）GB与中心星星之间的距离很小，这确保了高的（>8000-10000 K）Lyα H光谱温度，选择性激发Fe Ⅱ;（3）Fe Ⅱ能级的布居以及相应的受激发射通道的开放，它与自发跃迁一起产生一个辐射循环，其中单个Fe Ⅱ离子可以多次吸收Lyα发射。
We consider the origin of the anomalously high intensity of the ultraviolet Fe II λλ2507/2509 Å lines observed with high spatial and spectral resolutions from gas blobs (GBs) near η Carinae. This rare effect in stellar spectra is attributable to a combination of several factors: (1) the high hydrogen density(>108cm−3) that ensures the blockingof the Lyman continuum by GBs and, accordingly, the formation of a cold H I region with completely ionized Fe atoms; (2) the small distance between the GBs and the central star that ensures a high (>8000–10000 K) Lyα H spectral temperature, which photoexcites Fe II selectively; and (3) the population of Fe II levels and, accordingly, the opening of a stimulated emission channel, which together with spontaneous transitions creates a radiative cycle where a single Fe II ion can multiply absorb Lyα emission.