周期性重复快速射电暴双星模型再研究  

Revisiting the White Dwarf-Neutron Star Binary Model on the Periodic Activity of Repeating FRBs

作　　者：林一清[1,2] 程再军 Lin Yiqing;Cheng Zaijun(Fujian Provincial Key Laboratory of Optoelectronic Technology and Devices,Xiamen University of Technology,Xiamen 361024,China;School of Optoelectronic&Communication Engineering,Xiamen University of Technology,Xiamen 361024,China)

机构地区：[1]厦门理工学院福建省光电技术与器件重点实验室,福建厦门361024 [2]厦门理工学院光电与通信工程学院,福建厦门361024

出　　处：《天文研究与技术》2023年第3期198-203,共6页Astronomical Research & Technology

基　　金：福建省自然科学基金(2021J011215);厦门市青年创新基金(3502Z20206077)资助.

摘　　要：在椭圆轨道的致密双星模型作为周期性重复快速射电暴(Fast Radio Bursts,FRBs)起源的基础上,考虑引力辐射对快速射电暴周期性行为的影响。这个双星系统包含一个具有强偶极磁场的中子星和一个磁化的白矮星。当白矮星充满它的洛希瓣时,物质将通过内拉格朗日点转移到中子星表面。由于角动量守恒,白矮星可能在一次爆发之后被踢开,接着在演化过程中由于引力辐射再次充满洛希瓣,实现再次爆发。这种情况下,快速射电暴的周期对应于双星轨道周期P_(orb),而它与两次质量转移时间间隔Δt之间的关系是能否显现周期性行为的关键因素。很明显,Δt≈P_(orb)或者Δt<P_(orb)是周期性行为显现的必要条件。反之,如果Δt>>P_(orb),周期性将很难观测到。结果表明,只有相对较长周期的快速射电暴才能显示周期性行为,这表明目前仅有的两个周期性快速射电暴都对应于较长的周期是合理的。Fast Radio Bursts(FRBs)are transient and bright radio pulses from cosmological origins,which have two types:repeating FRBs and non-repeating FRBs.Based on the eccentric binary model for the origin of the periodic FRBs,we consider the effects of gravitational-wave(GW)radiation on the periodic activity of repeating FRBs.The compact binary system composed of a neutron star(NS)with a strong bipolar magnetic field and a magnetic white dwarf(WD)may be able to explain the repeated behavior of repeating FRBs.When WD fills its Roche lobe,mass transfer will occur through the inner Lagrange point to the surface of the NS.After an explosion,the WD may be kicked away owing to the conservation of angular momentum,and refills its Roche lobe at the next periastron,due to the decrease of orbital separation through GW radiation to realize another.In this scenario,the period of the repeating FRBs should be equivalent to the orbital period P_(orb).Thus,the relation between P_(orb)and the time interval of two adjacent mass-transfer processesΔt is a key factor that may determine whether the periodic activity can show up.Obviously,Δt≈P_(orb)orΔt<P_(orb)is a necessary condition for the periodic activity to appear.On the contrary,forΔt>>P_(orb),the periodicity will be hard to discover.The results show that the periodic activity is more likely to show up for relatively long periods,which may be the reason that only two sources having been claimed to have periodic activity,both correspond to relatively long periods.

关 键 词：快速射电暴 白矮星 中子星 引力辐射 致密双星 

分 类 号：P172[天文地球—天文学]