arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2211.12945astro-ph.HE
收藏

吸积与螺旋桨状态之间转变中的滞后效应

On the hysteresis effect in transitions between accretion and propeller regimes

Sercan Çıkıntoğlu, K. Yavuz Ekşi

AI总结:

本文研究吸积盘与磁层相互作用中螺旋桨状态与吸积状态之间转变的滞后效应,通过计算质量通量比例发现吸积状态开始与结束时的快度参数不同,从而解释了低质量X射线双星谱态转变中的光度差异。

摘要:

一些关于吸积盘与磁层相互作用的观测和数值模拟表明,吸积可以在螺旋桨状态下继续进行。当阿尔文半径位于共转半径之外时,物质会攀升到高纬度区域,在那里阿尔文面位于平衡面之内,从而能够发生吸积。我们计算了吸积盘中能够吸积到中子星上的质量通量比例,该比例取决于快度参数以及自转轴与磁轴之间的倾角。我们发现,在一个狭窄的快度参数范围内,阿尔文面与平衡面会在两个不同的临界纬度处相交。当系统从螺旋桨状态过渡到吸积状态(爆发初始上升阶段)时,吸积盘已经较厚,位于这两个临界纬度之间的盘部分无法发生吸积。在从吸积状态过渡到螺旋桨状态(爆发衰减阶段)时,吸积盘较薄,因此物质可以完全吸积,直到阿尔文半径移动到盘中间面处的平衡半径之外。因此,吸积状态开始时的快度参数小于其结束时的快度参数。其结果是,从螺旋桨状态到吸积状态的转变发生在比从吸积状态到螺旋桨状态的转变更高的光度下。我们讨论了这些结果对低质量X射线双星所表现出的谱态转变的启示。

英文摘要:

Some observations and numerical simulations of disc-magnetosphere interaction show that accretion can proceed in the propeller regime. When the Alfvén radius is beyond the corotation radius, matter climbs up to the high latitudes where the Alfvén surface is inside the equilibrium surface and can accrete. We calculate the fraction of the mass flux in the disc that can accrete onto the neutron star depending on the fastness parameter and the inclination angle between rotation and magnetic axis. We find that, for a narrow range of the fastness parameter, the Alfvén and the equilibrium surfaces intersect at two different critical latitudes. While the system is transiting from the propeller to the accretion regime (the initial rise of an outburst), the disc is already thick and the part of the disc between these two critical latitudes cannot accrete. In transitions from the accretion to the propeller regime (decay of an outburst), the disc is thin, hence, full accretion of matter proceeds until the Alfvén radius moves beyond the equilibrium radius at the disc-midplane. Therefore, the accretion regime commences at a smaller fastness parameter than it ceases. As a result, the transition from the propeller to the accretion regime occurs at a luminosity higher than the transition from the accretion to the propeller regime. We discuss the implications of our results for spectral transitions exhibited by low-mass X-ray binaries.

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。

↑