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arXiv 1310.2173astro-ph.HE
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具有晚型巨星伴星的X射线双星的长时间尺度变率

Long time-scale variability of X-ray binaries with late type giant companions

E. Filippova, M. Revnivtsev, E. R. Parkin

摘要:

在本文中,我们提出并研究了一种物理机制,它可以导致产生噪声的质量吸积率的低质量X射线双星的时间尺度上的轨道周期的系统。我们认为调制的质量捕获的紧凑的对象从伴星的恒星风的二进制晚型巨人,系统通常有很长的轨道周期。我们表明,即使没有偏心率的质量吸积率的变化与特征时间尺度接近的轨道周期的二元系统内的风物质的流体动力学相互作用。变化的原因是一个未开发的湍流运动(扰动运动没有显着的涡)的风物质附近的紧凑的对象。我们的结论得到支持的三维模拟与两个不同的流体动力学代码的基础上拉格朗日和欧拉的方法-SPH代码GADGET和欧拉代码PLUTO。在这项工作中,我们假设风的质量损失率的二次是在$(0.5-1)\times10^{-7} M_\odot$ /年的水平,需要产生可观察到的变化的质量吸积率的主要。这个值比这类单颗巨星的估计值要高,但在双星系统中,晚型巨星的质量损失率更高的例子确实存在。我们的模拟表明,被紧凑的物体拦截的恒星风物质可能会产生类似于吸积盘日冕/风的观测外观,并可以通过X射线吸收线的高能量分辨率观测来检测,特别是重元素的高度电离离子。

英文摘要:

In this paper we propose and examine a physical mechanism which can lead to the generation of noise in the mass accretion rate of low mass X-ray binaries on time-scales comparable to the orbital period of the system. We consider modulations of mass captured by the compact object from the companion star's stellar wind in binaries with late type giants, systems which usually have long orbital periods. We show that a hydrodynamical interaction of the wind matter within a binary system even without eccentricity results in variability of the mass accretion rate with characteristic time-scales close to the orbital period. The cause of the variability is an undeveloped turbulent motion (perturbed motion without significant vorticity) of wind matter near the compact object. Our conclusions are supported by 3D simulations with two different hydrodynamic codes based on Lagrangian and Eulerian approaches -- the SPH code GADGET and the Eulerian code PLUTO. In this work we assume that the wind mass loss rate of the secondary is at the level of $(0.5-1)\times10^{-7} M_\odot$/year, required to produce observable variations of the mass accretion rate on the primary. This value is higher than that, estimated for single giant stars of this type, but examples of even higher mass loss rate of late type giants in binaries do exist. Our simulations show that the stellar wind matter intercepted by the compact object might create observational appearances similar to that of an accretion disc corona/wind and could be detected via high energy resolution observations of X-ray absorption lines, in particular, highly ionized ions of heavy elements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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