Studies on x-ray emission mechanisms of stars by a collisional-radiative model including effects of radiation transfer

我们的研究目标是阐明恒星的X射线发射机制。为了完成我们的研究，我们首先发展了一个新的恒星风的碰撞辐射模型，包括辐射传输。然后，我们将我们的星风模型应用于X射线卫星观测到的X射线谱线，得到了恒星周围的X射线辐射区、星风密度、星风温度等信息。(1)各种类氦（C，N，O，Ne，Mg，Si，S）离子的高精度碰撞辐射模型的发展用蒙特卡罗方法研究辐射输运问题还处于初步模型阶段。(2)KLM壳层铁离子碰撞辐射模型的发展及其在实验室等离子体中的应用。铁离子的模型被应用到螺旋等离子体（大螺旋装置（LHD）在国家聚变科学研究所）的高精度建模。(3)构造一个包括三个分量的多普勒模型，多普勒频移来源于星风的速度分布，星风中介质的散射，以及填充因子。(4)用多普勒模型分析了Chandra和XMM-Newton两颗X射线卫星观测到的早期型星，并讨论了星周X射线辐射区。此外，还分析了朱雀卫星（2005年发射）的恒星X射线发射谱。我们发现zeta-pup的x射线辐射区域靠近星星，而tau-sco的x射线辐射区域远离星星（Yamamoto et al.2007）。我们计划进行以下工作：更精确地分析x射线辐射谱，从现有的玩具模型发展到实用的辐射传输模型，研究实用的非平衡等离子体模型。然后，利用该模型分析了天文等离子体和太阳等离子体。

Our research goal is to elucidate X-ray emission mechanisms of stars. To accomplish our study, at first we developed a new collisional-radiative model of stellar wind from stars including the radiation transfer. Next we applied our stellar wind model to the observed X-ray spectral lines with X-ray satellites to reveal the X-ray emitted region around stars, the density of the stellar wind, the temperature of the stellar wind, and so on.The result of our study is as follows.(1) Developments of a high precise collisional-radiative model of various helium-like (C, N, O, Ne, Mg, Si, S) ions. Inclusions of radiation transfer by Monte Carlo method are at a stage of a toy model.(2) Developments of a collisional-radiative model on KLM-shell Fe ions and applications to laboratory plasma. The model for Fe ions was applied to helical plasmas (large helical device (LHD) at the National Institute for Fusion Science) for highly precise modeling.(3) Constructions of a Doppler model including three components, the doppler shift derived from a velocity distribution of stellar winds, absorptions by mediums in stellar winds, and filling factors.(4) Analysis of early type stars obtained with X-ray satellites (Chandra and XMM-Newton) by the doppler model, and discussions of X-ray emission regions around stars. Furthermore X-ray emission spectra of stars by Suzaku satellite (launched in 2005) were analyzed. We obtained that x-ray emission regions of zeta-pup are near a star, on the other hand these of tau-sco are far from a star (Yamamoto et al.2007).We plan as follows, more precise analysis of x-ray emission spectra, a development from current toy model to a practical radiation transfer model, researches of practical non-equilibrium plasma model. Then, astronomical plasmas and solar plasmas are analyzed by the model.