摘要
统计研究了63对双星系统中的72颗中子星(NS)的测量质量,其中包括18对X射线双星(XB)、9对双中子星(DNS)、4对中子星主序星系统(NSMS)、32对中子星白矮星系统(NSWD).运用Monte-Carlo随机抽样的方法,模拟出NS的质量分布,然后基于模拟结果进行统计分析.通过质量的统计研究,发现其质量呈双峰分布,分别集中在(1.328±0.220)M_⊙和(1.773±0.416)M_⊙.值得注意的是,在不考虑DNS的情况下,发现其质量分布仍然是双峰分布,质量集中在(1.360±0.337)M_⊙和(1.854±0.322)M_⊙.18颗DNS质量为单峰分布,平均质量为(1.330±0.0089)M_⊙.NS质量的双峰结构显示出,其可能有两种诞生方式.认为可能是铁核塌缩超新星爆发和电子俘获超新星爆发.DNS质量的单峰结构意味着DNS诞生演化机制可能与其他双星系统不同.为了进一步研究中子星质量分布的特性,将53颗测量到自旋周期的NS在20 ms处分为两组,分别为毫秒中子星(MSP,Ps≤20 ms)和正常中子星(PSR,Ps>20 ms),发现这两类NS质量也都呈现出双峰分布,而且MSP的平均质量要比PSR的平均质量大～0.22 M_⊙.这表明NS在诞生后吸积约0.22 M_⊙的物质时,将可能成为MSP.根据NS质量与周期在M-Ps图上的分布,拟合出质量与周期之间的关系为:M=1.4+(Ps/ms)^(-3/2)M_⊙.
The measured masses of 72 neutron stars （NSs） in 63 pairs of binary systems are studied in this paper, including 18 X-ray binary systems （XBs）, 9 double neutron star systems （DNSs）, 4 neutron star-main sequence binary systems （NSMSs）, and 32 neutron star-white dwarf binary systems （NSWDs）. We use the method of Monte-Carlo random sampling to deal with the uncertainty of measured masses to in-crease the accuracies of statistical bimodal distribution, with the first results. We find that the measured masses have a peak around （1.328±0.220） M, and a much wider second peak at （1.773±0.416） M, respectively. It is worth noting that, even though the DNSs are excluded, the mass distribution is still bimodal and peaked respectively at （1.360±0.337） Me and （1.854±0.322） M⊙. The average mass of 18 DNSs is （1.330±0.0089） M⊙. Through the above mass distribution, it can be clearly seen that DNS has a little influence on the mass distribution of NS, and the distribution of NS mass also implies that there are two birth modes of NSs. We think that they are the nuclear collapse supernova explosion and the electron capture supernova eruption. The single peak structure of DNS mass implies that the evolution mechanism of DNS may be different from other binary systems. In order to further study the characteristics of neutron star mass distribution, we divide the 53 NSs with measured mass into two groups, the millisecond neutron star （MSP, the spin period Ps ≤ 20 ms） and normal neutron star （PSR, Ps 〉 20 ms）. We find that their mass distributions also show the bimodal structure, and the average mass of MSP is-0.22 Me larger than the average mass of PSR. This indicates that the spin of NS will reach milliseconds after the accretion of about 0.22 Me. According to the distribution of NS mass and period on the M-Ps diagram, the fitting results of the M-Ps relation is M = 1.4 ＋ （Ps/ms）-3/2 M⊙.
作者
刘鹏
张洁
支启军
王德华
尚伦华
杨佚沿
潘元月
LIU Peng1, ZHANC Jie1, ZHI Qi-jun2,3, WANG De-hua2,3, SHANG Lun-hua2,3, YANG Yi-yan4, PAN Yuan-yue5(1. Physics and Space Science College, China West Normal University, Nanchong 637009; 2. School of Physics and Electronic Sciences, Guizhou Normal University, Guiyang 550001; 3. Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing, Guiyang 550001; 4.School of Physics and Electronic Sciences, Guizhou Education University, Guiyang 550018） （5 Department of Physics and Optoelectronies, Xiangtan University, Xiangtan 411105)
出处
《天文学报》
CSCD
北大核心
2018年第3期57-70,共14页
Acta Astronomica Sinica
基金
国家自然科学基金项目(11273020
U1731238
11565010)
贵州省核天体物理与脉冲星科技创新团队(黔科合人才团队(2015)4015)
贵州省百层次创新人才项目(黔科合人才(2016)4008)
贵州省教育厅青年科技人才成长项目(黔教合KY字[2017]204)资助
关键词
恒星
中子
双星
质量
方法
统计
stars
neutron
binaries
mass
methods
statistical
