中子星中心致密天体的双星起源

Binary Origin of the Neutron Star Central Compact Objects

探讨了认为中心致密天体(CCO)起源于双星的可能性.首先, CCO与正常遗迹脉冲星有着相似的平均自旋周期,但CCO的平均表面磁场强度(B^5.4×10^(10)Gs)低于正常遗迹脉冲星(B^7.7×10^(12)Gs)~2个量级.同时,几乎所有的正常遗迹脉冲星均分布在爱丁顿吸积加速线以上,而CCO全部分布在自旋加速线以下.因此怀疑CCO可能起源于双星吸积加速过程.其次,基于中子星再加速理论,分析了CCO可能的双星演化过程:双星系统中, CCO以M^1017g·s^(-1)的吸积率,经过~106yr的时间共吸积△M^10^(-2)M⊙的物质,其自旋周期将会从P^10 s降低至P^0.1 s,表面磁场强度将会从B^10^(12)Gs降低至B^1010Gs.考虑到~106yr的演化时标远大于CCO遗迹的年龄(~0.3–7 kyr),猜想CCO可能是双星系统中第1颗恒星超新星爆发的产物,而第2颗恒星超新星爆发后双星解体,留下CCO和第2颗恒星的超新星遗迹.该模型预言在CCO附近可能存在一颗年轻的正常脉冲星(P^0.02 s, B^1012Gs),并期望未来的射电望远镜和高能探测器能够进行搜寻.

The possibility of the binary origin for the central compact objects(CCOs)is probed in this paper.Firstly,we find that the CCOs share the similar average spin period to the normal supernova remnant(SNR)pulsars,however,the average surface magnetic field strength of CCOs(B^5.4×1010 Gs)is lower than the normal SNR pulsars(B^7.7×1012 Gs)by^2 orders of magnitudes.Meantime,we also find that almost all the normal SNR pulsars lie in the position above the spin-up line,while all the CCOs lie in the position under the spin-up line.Therefore,we doubt that CCOs may origin from the accretion induced spin-up process in the binaries.Secondly,we analyze the possible binary evolution process of CCOs based on recycling theory of the neutron stars:in the binary,a CCO can accrete the△M^10-2 M⊙matter with the accretion rate ofM^1017 g·s-1 during the time of^106 yrs,then its spin period will decrease from P^10 s to P^0.1 s,and its surface magnetic field strength will decrease from B^1012 Gs to B^1010 Gs.Considering that the evolution timescale of^106 yr is far longer than the age of the SNRs containing CCOs(~0.3–7 kyr),we suppose that CCOs may be the products of the supernova of the first star in the binary,and the binary is disintegrated during the supernova of the second star,which leaves a CCO and the SNR of the second star.This model predicts that there may exit a young normal pulsar near the CCO(P^0.02 s,B^1012 Gs),and we expect that the radio telescope and high energy detector can survey these sources in the future.