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首页> 外文期刊>PASJ: Publications of the Astronomical Society of Japan >Reproductions of super-orbital X-ray light-curves with the precessing accretion ring model and implications on accretion flows through accretion rings
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Reproductions of super-orbital X-ray light-curves with the precessing accretion ring model and implications on accretion flows through accretion rings

机译：具有进动吸积环模型的超轨道X射线光曲线的复制及其对通过吸积环的吸积流的影响

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X-ray light-curves of three X-ray pulsars, SMC X-1, LMC X-4, and Her X-1, folded with their respective super-orbital periods, are shown to be well reproduced by a model in which X-rays from a compact object towards us are periodically obscured by a precessing ring at the outermost part of an accretion disk around the central object. A situation is considered in which matter from a companion star flows into a gravitational field of a compact star carrying a certain amount of specific angular momentum and first forms a geometrically thick ring-tube along the Keplerian circular orbit. For the model to well fit to the observations, it is necessary that the optical depth of the ring-tube for Compton scattering, τ ? 1 ～ 2, the ring matter temperature, T ? 105 ～ 106?K, and the ionization parameter, ξ ? 102?erg?cm?s?1 due to X-ray heating from the central X-ray source.From simple energetics- and perturbation-arguments, we find that a precession of such a ring is rather stable and can be excited in the T and ξ ranges. The time during which matter accumulates in the ring is estimated to be ～106?s, and is shown to be comparable to the time for an accretion disk to extend from the ring. It is discussed that in the above T and ξ ranges, the ring-tube matter could become thermally unstable. Then, relatively high density regions in the ring-tube further cool down and tend to shrink to the tube center. The flow across the ring circulating flow should excite turbulent motions, and angular momenta of the matter would be effectively transferred across the tube. Finally, a steady flow should be established from the companion star through the accretion ring to the accretion disk towards the central compact star.
机译：三种X射线脉冲星SMC X-1，LMC X-4和Her X-1的X射线光曲线，分别折叠成各自的超轨道周期，可以很好地再现其中X的模型。从紧致物体射向我们的射线会被围绕中心物体的吸积盘最外层的进动环周期性地遮挡。考虑一种情况，来自伴星的物质流入带有一定量的特定角动量的紧凑型恒星的引力场，并首先沿开普勒圆形轨道形成几何上较粗的环形管。为了使模型与观测值很好地吻合，对于康普顿散射，环形管的光学深度τ？ 1〜2，环物质温度，T？ 105〜106？K，电离参数ξ？由于来自中心X射线源的X射线加热而产生的102？erg·cm？s？1。从简单的能量学和微扰论证，我们发现这种环的进动相当稳定，并且可以在激发中被激发。 T和ξ范围。物质在环中累积的时间估计为〜106？s，显示出与吸积盘从环中伸出的时间相当。讨论了在上述T和ξ范围内，环管物质可能变得热不稳定。然后，环形管中相对较高密度的区域进一步冷却并趋于收缩至管中心。环流中的流动会激起湍流运动，物质的角动量将有效地传递到整个管子上。最后，应建立一个稳定的流动，从伴星通过吸积环到吸积盘流向中心致密星。

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