Line Ratios for Solar Wind Charge Exchange with Comets
Line Ratios for Solar Wind Charge Exchange with Comets
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DOI：
10.3847/1538-4357/aa7752
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发表时间：
2017-07
期刊：
影响因子：
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通讯作者：
P. D. Mullen;R. Cumbee;D. Lyons;L. Gu;J. Kaastra;R. Shelton;P. Stancil
中科院分区：
文献类型：
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作者：
P. D. Mullen;R. Cumbee;D. Lyons;L. Gu;J. Kaastra;R. Shelton;P. Stancil
电荷交换（CX）已经出现在X射线发射模型作为一个重要的过程，必须考虑在许多天体物理环境，特别是彗星。彗星是太阳风离子和彗星中性粒子之间相互作用的宿主，以促进太阳风电荷交换（SWCX）。X射线天文台为天文学家和天体物理学家提供了许多X射线发射彗星的数据，如果没有可靠的CX数据，这些彗星就不可能精确建模。在这里，我们利用一套精简的计算机程序，将多通道朗道-齐纳理论和级联模型的X射线发射产生的各种裸和非裸离子单电子捕获（SEC）碰撞的横截面和X射线线比。也就是说，我们考虑太阳风成分C，N，O，Ne，Na，Mg，Al和Si的裸露和类H离子与彗星中性粒子H2O，CO，CO2，OH和O之间的碰撞。为了验证这些数据的应用，我们使用DAC中的CX软件包模拟了彗星C/2000 WM 1（线性）的X射线发射，并发现与XMM-牛顿RGS探测器的观测结果非常一致。我们的分析表明，X射线强度由带有H的SWCX主导，而H2O起次要作用。这是第一次，据我们所知，CX横截面已实施到X射线光谱拟合包，以确定彗星大气中的H到H2O的比例。CX数据集被纳入建模软件包dac和Kronos。
Charge exchange (CX) has emerged in X-ray emission modeling as a significant process that must be considered in many astrophysical environments—particularly comets. Comets host an interaction between solar wind ions and cometary neutrals to promote solar wind charge exchange (SWCX). X-ray observatories provide astronomers and astrophysicists with data for many X-ray emitting comets that are impossible to accurately model without reliable CX data. Here, we utilize a streamlined set of computer programs that incorporate the multi-channel Landau–Zener theory and a cascade model for X-ray emission to generate cross sections and X-ray line ratios for a variety of bare and non-bare ion single electron capture (SEC) collisions. Namely, we consider collisions between the solar wind constituent bare and H-like ions of C, N, O, Ne, Na, Mg, Al, and Si and the cometary neutrals H2O, CO, CO2, OH, and O. To exemplify the application of this data, we model the X-ray emission of Comet C/2000 WM1 (linear) using the CX package in SPEX and find excellent agreement with observations made with the XMM-Newton RGS detector. Our analyses show that the X-ray intensity is dominated by SWCX with H, while H2O plays a secondary role. This is the first time, to our knowledge, that CX cross sections have been implemented into a X-ray spectral fitting package to determine the H to H2O ratio in cometary atmospheres. The CX data sets are incorporated into the modeling packages SPEX and Kronos.