标题： 毫秒脉冲星的质量 显示英文标题

标题： The Mass of a Millisecond Pulsar

摘要： 我们报告了使用加利福尼亚理工学院-帕克斯-斯温本仪器 II（CPSR2）对低质量毫秒脉冲星 PSR J1909-3744 近两年的计时观测结果，这是一种能够提供前所未有的计时精度的新设备。每日观测得到的加权均方根残差为 74 纳秒，表明系统误差极低。 我们大大改进了对 PSR J1909-3744 的视差和自行测量，得出的距离为$1.14^{+0.04}_{-0.03}$千秒差距，横向速度为$(200^{+7}_{-6})$千米每秒$^{-1}$。该系统的轨道偏心率仅为 1.35(12)$\times10^{-7}$，是迄今记录的最小值。 自其发现以来，快速旋转的毫秒脉冲星的质量一直是个谜，再加速假说认为它们是较重的天体，而白矮星吸积诱导塌缩则更符合小于钱德拉塞卡极限的中子星。幸运的是，PSR J1909-3744 是一个边缘系统，我们的数据使得我们可以精确测量夏皮罗延迟的范围和形状，从而首次确定了一颗毫秒脉冲星的质量，即$m_p = (1.438 \pm 0.024) M_\odot$。 PSR J1909-3744 的质量处于双中子星系统中适度再加速脉冲星质量范围内上限的位置，这与再加速假说一致。 似乎通过吸积小于$0.2 M_\odot$就可以产生毫秒脉冲星。 显示英文摘要

摘要： We report on nearly two years of timing observations of the low-mass binary millisecond pulsar, PSR J1909-3744 with the Caltech-Parkes-Swinburne Recorder II (CPSR2), a new instrument that gives unprecedented timing precision. Daily observations give a weighted rms residual of 74 ns, indicating an extremely low level of systematic error. We have greatly improved upon the previous parallax and proper motion measurements of PSR J1909-3744, yielding a distance of $1.14^{+0.04}_{-0.03}$ kpc and transverse velocity of $(200^{+7}_{-6})$ km s$^{-1}$. The system's orbital eccentricity is just 1.35(12)$\times10^{-7}$, the smallest yet recorded. Since their discovery, the masses of the rapidly rotating millisecond pulsars have remained a mystery, with the recycling hypothesis arguing for heavy objects, and the accretion-induced collapse of a white dwarf more consistent with neutron stars less than the Chandrashkar limit. Fortuitously, PSR J1909-3744 is an edge-on system, and our data have allowed the measurement of the range and shape of the Shapiro delay to high accuracy, giving the first precise determination of a millisecond pulsar mass to date, $m_p = (1.438 \pm 0.024) M_\odot$. The mass of PSR J1909-3744 is at the upper edge of the range observed in mildly recycled pulsars in double neutron star systems, consistent with the the recycling hypothesis. It appears that the production of millisecond pulsars is possible with the accretion of less than $0.2 M_\odot$.