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Structure and Evolution of the Accretion Flow in Be/X-ray Binaries

Be/X射线双星吸积流的结构和演化

基本信息

批准号：
16540218
负责人：
OKAZAKI Atsuo
金额：
$ 1.98万
依托单位：
Hokkai-Gakuen University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540218/
关键词：
accretion disks Be stars Be X-ray binaries decretion disks neutron stars resonance tidal interaction X-ray transients

项目摘要

We have studied the accretion flow in Be/X-ray binaries, by performing three dimensional Smoothed Particle Hydrodynamics simulations. To optimize the resolution and computational efficiency of our simulations, we have elected to break the decretion and accretion portions of the computation into two separate, but linked parts. The first focused on the decretion of the Be disk under the combined gravitational influence of the B-star and neutron star. The second part of the simulation focused on the accretion disk around the neutron star, with the phase-dependent mass transfer from the Be disk simulation used as an outer boundary condition for the accretion process. We have obtained the following conclusions.1. A persistent accretion disk is formed around the neutron star, irrespective of the orbital parameters. The accretion disk shrinks at the periastron passage of the Be star and restores its radius afterwards.2. The accretion disk is smaller in the case of a higher orbital eccentricit … More y.3. The ram pressure due to the phase-dependent mass transfer from the Be-star disk excites a one-armed, trailing spiral structure in the accretion disk. The inward propagation of the spiral wave significantly enhances the mass-accretion rate onto the neutron star.4. The accretion disk evolves through three distinct phases. In the first "developing phase", the disk is formed and develops towards a nearly Keplerian disk. In the second "transition phase", the disk is approximately Keplerian and grows with time. The mass-accretion rate increases as the disc grows. In the final quasi-steady state, the mass-accretion rate is on average balanced with the mass-transfer rate from the Be disk and exhibits a regular orbital modulation.5. The mass-accretion rate has a broad peak at a phase significantly later than periastron. This peak stems from the inward-propagating, one-armed spiral wave, and the phase lag results from a combination of the time for wave excitation and the wave propagation time. Less

利用三维光滑粒子流体动力学方法研究了Be/X射线双星的吸积流。为了优化我们模拟的分辨率和计算效率，我们选择将计算的衰减和吸积部分分成两个独立但相互关联的部分。第一部分研究了Be盘在B-星星和中子星星引力共同作用下的衰变。模拟的第二部分集中在中子星星周围的吸积盘，与相位相关的质量转移作为吸积过程的外边界条件，从Be盘模拟使用。我们得到了以下结论。1.无论轨道参数如何，中子星星周围都会形成一个持久的吸积盘。吸积盘在Be星星的近星点通道处收缩，之后恢复半径.在轨道偏心率较高的情况下，吸积盘较小 ...更多信息 y.3.由于相依赖的质量转移从Be星盘的冲压压力激发一个单臂，拖尾螺旋结构的吸积盘。螺旋波的向内传播显著提高了中子星的质量吸积率.吸积盘的演化经历了三个不同的阶段。在第一个“发展阶段”，盘形成并向近似开普勒盘发展。在第二个“过渡阶段”，磁盘近似开普勒和增长的时间。质量吸积率随着圆盘的增大而增大。在最终的准稳态中，质量吸积速率与Be盘的质量转移速率平均平衡，并呈现出规则的轨道调制.质量吸积率在一个明显晚于近星点的阶段有一个宽的峰值。该峰值源于向内传播的单臂螺旋波，并且相位滞后由波激发时间和波传播时间的组合产生。少