作　　者： ; ; ; ; ; (潘元月）;

机构地区： 中国科学院国家天文台

出　　处： 《天文学报》 2013年第6期514-526,共13页

摘　　要： 通过调研高质量X射线源(HMXB)、低质量X射线源(LMXB)、双中子星(DNS)系统、中子星-白矮星(NS-WD)双星系统这4类不同系统中中子星质量的测量方法,收集了40套系统的轨道参数,利用boot-strap方法和蒙特卡罗方法,重建了46颗中子星测量质量的似然概率曲线.基于模拟结果的统计分析,表明X射线中子星系统和射电脉冲星系统的中子星质量遵循不同的分布.另外,Bayesian统计针对这4类不同的系统分别给出的最可几的概率密度分布分别为:(1.340±0.230)M_☉,(1.505±0.125)M_☉,(1.335±0.055)M_☉和(1.495±0.225)M_☉.值得注意的是高质量X射线源和双中子星系统的中子星质量都比另外两组系统要小大约0.16 M_☉,这个结果与脉冲星通过吸积大约0.2 M_☉物质加速到毫秒量级的理论模型相一致.如果将高质量X射线源和低质量X射线源分别看作是双中子星系统和脉冲星-白矮星系统的前身系统,那么吸积效应对高质量X射线源的中子星质量的影响势必非常小,其质量分布应该非常接近中子星形成时的初始质量分布,而低质量X射线源和脉冲星-白矮星系统则应已经过充分的吸积过程,从而与初始质量分布产生了较大的偏移. We investigate the measurement of neutron star masses in different population of binaries. Based oil the collection of the orbital parameters of 40 systems （46 sources）, we apply the boot-strap method together with the Monte Carlo method to reconstruct the likelihood curves for each source separately. The cumulative analysis of the simulation re- sult shows that the neutron star masses in X-ray systems and radio systems obey different distributions, and no evidence for tile bimodal distribution could be found. Employing the Bayesian statistical techniques, we find that the most likely distributions for the high mass X-ray binaries （HMXBs）, low mass X-ray binaries （LMXBs）, double neutron star （DNS） systems, and neutron star-white dwarf （NS-WD） binary systems are （1.340±0.230） Mo, （1.505±0.125） Mo, （1.335±0.055） Mo, and （1.495±0.225） Me, respectively. The statistical distribution has no significant deviation from the standard neutron star formation mecha- nism. It is noticed that the statistical results of the center masses of LMXBs and NS-WD systems are significantly higher than the other groups by about 0.16 Mo, which could be regarded as the evidence of accretion episodes. And if we regard the HMXBs and LMXBs as tile progenitors of DNS and NS-WD systems, then we can draw the conclusion that the accretion effect must be very week during the evolution trajectory from HMXBs to DNS systems, and this could be the reason wily the masses of DNS systems have such a narrow distribution.

关 键 词： 脉冲星 普通 恒星 中子 方法 统计

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