Spin evolution of neutron stars in wind-fed high-mass X-ray binaries
Spin evolution of neutron stars in wind-fed high-mass X-ray binaries
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DOI：
10.1093/pasj/psaa087
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发表时间：
2020-08
期刊：
影响因子：
--
通讯作者：
S. Karino
中科院分区：
文献类型：
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作者：
S. Karino
观测到的OB型高质量X射线双星(HMXB)的X射线脉冲周期通常长于100秒。认为中子星的强磁场与风物质之间的相互作用可以产生如此长的脉冲周期。在这项研究中，我们跟踪NS的自旋演化，考虑了磁场和风物质之间的相互作用。在这条线上，作为新的挑战，我们同时解决了中子星磁场的演化，另外我们还关注了施主风属性的影响。结果得到了中子星在出生后在喷射器阶段持续一段时间，然后迅速向下旋转，达到准平衡，然后逐渐向上旋转的演化轨迹。这种演化与以前的研究类似，但我们发现，它的主导物理依赖于施主风的速度。当风速较大时，由于磁场的抑制，会发生自旋下降，而在慢速风吸积中，经典的螺旋桨效应和沉降吸积壳会导致快速自旋下降。由于施主的风速可以依赖于辐照的X射线光度，因此风载HMXB中子星的自旋演化轨迹可能比我们想象的要复杂得多。
The observed X-ray pulse period of OB-type high-mass X-ray binary (HMXB) pulsars are typically longer than 100 seconds. It is considered that the interaction between the strong magnetic field of neutron star and the wind matter could cause such a long pulse period. In this study, we follow the spin evolution of NS, taking into account the interaction between the magnetic field and wind matter. In this line, as new challenges, we solve the evolution of the magnetic field of the neutron star at the same time, and additionally we focus on the effects of wind properties of the donor. As the result, evolutionary tracks were obtained in which the neutron star spends some duration in the ejector phase after birth, then rapidly spins down, becomes quasi-equilibrium, and gradually spins up. Such evolution is similar to previous studies, but we found that its dominant physics depends on the velocity of the donor wind. When the wind velocity is fast, the spin-down occurs due to magnetic inhibition, while the classical propeller effect and settling accretion shell causes rapid spin-down in the slow wind accretion. Since the wind velocity of the donor could depend on the irradiated X-ray luminosity, the spin evolution track of the neutron star in wind-fed HMXB could be more complicated than considered.