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，该模型包含了辐射传输。接下来，我们将我们的恒星风模型应用于X射线卫星观测的X射线谱线，揭示了恒星周围的X射线发射区域、恒星风的密度、恒星风的温度等。我们的研究结果如下：(1)发展了各种类氦(C，N，O，Ne，Mg，Si，S)离子的高精度碰撞-辐射模型。用蒙特卡罗方法计算辐射传输的包裹体还处于玩具模型阶段。(2)荷兰壳铁离子碰撞-辐射模型的发展及其在实验室等离子体中的应用。将铁离子模型应用于螺旋等离子体(美国国家核聚变科学研究所的大型螺旋装置)进行了高精度的模拟。(3)建立了一个包括三个部分的多普勒模型，由恒星风的速度分布得到的多普勒频移，恒星风中介质的吸收，以及填充因子。(4)利用X射线卫星(钱德拉和XMM-牛顿)获得的早期类型恒星的多普勒模型，并讨论了恒星周围的X射线发射区。此外，还对2005年发射的铃鹿卫星的X射线发射光谱进行了分析。我们得到Zeta-pup的X射线发射区靠近恒星，而tau-SCO的X射线发射区远离恒星(Yamamoto et al.2007)。我们计划在以下方面进行更精确的X射线发射光谱分析，从目前的玩具模型到实用的辐射传输模型的发展，实用的非平衡等离子体模型的研究。然后，利用该模型对天文等离子体和太阳等离子体进行了分析。

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.