Revealing the fastest component of the DG Tauri outflow through X-rays
Revealing the fastest component of the DG Tauri outflow through X-rays
复制标题
通过 X 射线揭示 DG Tauri 流出速度最快的部分
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Z.
中科院分区：
文献类型：
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作者：
H. Guenther;S. Matt;Z.
上下文。一些T金牛座恒星表现出一种特殊的X射线光谱，这种光谱可以由具有不同吸收柱密度的两个分量模拟。目标。我们试图用外流模型来解释DG-Tau中的软X射线成分，DG-Tau是这些源中研究得最好的，并考虑了其他波长的观测。方法：研究方法。我们通过谱拟合来约束外流特性，并使用简单的半解析公式来描述加热X射线发射区的激波的特性。结果。X射线发射与其来自光学探测到的流出的最快和最内侧的分量是一致的。这种X射线发射组件只需要总质量损失的一小部分。我们最喜欢的型号要求S一号的冲击波速度在400到500公里之间。对于密度>；105×10~(-3)cm~(-3)，激波冷却区的所有维度都只有几个AU，所以即使在光学观测中也不能解决这个问题。结论。除了日冕和吸积点外，这种外流中的X射线发射机制也可能在其他吸收较少的金牛座恒星中起作用。
Context. Some T Tauri stars show a peculiar X-ray spectrum that can be modelled by two components with different absorbing column densities. Aims. We seek to explain the soft X-ray component in DG Tau, the best studied of these sources, with an outflow model, taking observations at other wavelengths into consideration. Methods. We constrain the outflow properties through spectral fitting and employ simple semi-analytical formulae to describe properties of a shock wave that heats up the X-ray emitting region. Results. The X-ray emission is consistent with its arising from the fastest and innermost component of the optically detected outflow. Only a small fraction of the total mass loss is required for this X-ray emitting component. Our favoured model requires shock velocities between 400 and 500 km s -1 . For a density >10 5 cm -3 all dimensions of the shock cooling zone are only a few AU, so even in optical observations this cannot be resolved. Conclusions. This X-ray emission mechanism in outflows may also operate in other, less absorbed T Tauri stars, in addition to corona and accretion spots.