Effects of Preionization in Radiative Shocks. II. Application to the Herbig–Haro Objects
Effects of Preionization in Radiative Shocks. II. Application to the Herbig–Haro Objects
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辐射冲击中的预电离效应 II。
DOI：
10.3847/1538-4365/aa6542
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
R. Sutherland
中科院分区：
文献类型：
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作者：
M. Dopita;R. Sutherland
在较早的一篇论文中，我们用完全自洽的方法处理了速度范围为20公里的激波中的预电离问题，S−1公里S−1。在这里，我们详细地研究了在激波辐射区产生的上游UV光子场在氢只被部分电离的20 KM S−1(KM S−1)范围内的效应。结果表明，由于非平衡预激等离子体的过热，激波的磁参数和马赫数都受到气体预电离态的强烈影响，而预电离态在很大程度上控制着激波的辐射光谱。我们使用这些模型来为HerBig-Haro天体提供特定的线诊断，这使得我们能够求解震前密度和激波速度，并且我们给出了HH34喷流的详细模型，它允许我们推导出激波条件、质量损失率、动量通量和喷流中的化学丰度。结果表明，难熔元素镁、钙、铁和镍比太阳值强0.22dex，这为前主序演化中的喷流发射机制提供了有趣的线索。
In an earlier paper we treated the preionization problem in shocks over the velocity range 20 km s−1 km s−1 in a fully self-consistent manner. Here we investigate in detail the effect of the upstream UV photon field generated in the radiative zone of shocks in the range in which hydrogen is only partly ionized 20 km s−1 ( km s−1). We show that, as a result of superheating in the nonequilibrium preshock plasma, both the magnetic parameter and the Mach number of the shock are strongly affected by the preionization state of the gas, which controls to a large extent the radiative spectrum of the shock. We use these models to provide specific line diagnostics for Herbig–Haro objects, which allow us to solve for both the preshock density and shock velocity, and we present detailed models of the HH 34 jet, which allows us to derive the shock conditions, mass-loss rate, momentum flux, and chemical abundances in the jet. We show that the refractory elements Mg, Ca, Fe, and Ni are enhanced by 0.22 dex over the solar values, which provides interesting clues about the jet-launching mechanism in pre-main-sequence evolution.
HH 1158：最低光度的外部照射 HERBIGâHARO 喷射机
DOI：
10.1088/2041-8205/815/2/l31
发表时间：
2015
期刊：
The Astrophysical Journal Letters
影响因子：
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作者：
Whelan
通讯作者：
Whelan