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首页> 外文期刊>The Astrophysical journal >X-RAY EMISSION LINE PROFILES FROM WIND CLUMP BOW SHOCKS IN MASSIVE STARS
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X-RAY EMISSION LINE PROFILES FROM WIND CLUMP BOW SHOCKS IN MASSIVE STARS

机译:恒星风团弓形冲击的X射线发射线轮廓

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摘要

The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two-component flow structure of wind and clumps using two "beta" velocity laws. While individual bow shocks tend to generate double-horned emission line profiles, a group of bow shocks can lead to line profiles with a range of shapes with blueshifted peak emission that depends on the degree of X-ray photoabsorption by the interclump wind medium, the number of clump structures in the flow, and the radial distribution of the clumps. Using the two beta law prescription, the theoretical emission measure and temperature distribution throughout the wind can be derived. The emission measure tends to be power law, and the temperature distribution is broad in terms of wind velocity. Although restricted to the case of adiabatic cooling, our models highlight the influence of bow shock effects for hot plasma temperature and emission measure distributions in stellar winds and their impact on X-ray line profile shapes. Previous models have focused on geometrical considerations of the clumps and their distribution in the wind. Our results represent the first time that the temperature distribution of wind clump structures are explicitly and self-consistently accounted for in modeling X-ray line profile shapes for massive stars.
机译:在将光谱数据与大质量恒星风中发生的物理过程联系起来时,结构化流动的后果仍然是紧迫的话题。在先前的论文中,我们的小组报告了通过刚性球形块的高超音速流动的流体动力学模拟,以探索可能在风团周围形成的弓形激波的结构。在这里,我们报告由这种弓形冲击形态产生的发射线的轮廓。为了计算排放线轮廓,我们采用两个“β”速度定律采用风和团块的两部分流动结构。尽管单个弓形冲击往往会产生双角发射线轮廓,但一组弓形冲击会导致线形具有一系列蓝移峰值发射的形状,该峰形取决于束间风介质对X射线的光吸收程度,流动中团块结构的数量以及团块的径向分布。使用两个贝塔定律规定,可以推导出整个风中的理论排放量和温度分布。排放量趋于成为幂律,并且温度分布在风速方面很宽。尽管仅限于绝热冷却,但我们的模型强调了弓形冲击效应对恒星风中热等离子体温度和发射度量分布的影响及其对X射线线轮廓形状的影响。先前的模型集中于团块的几何考虑及其在风中的分布。我们的结果代表了在对大质量恒星的X射线线轮廓形状进行建模时,风团结构的温度分布首次得到明确和自洽的解释。

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