二阶后牛顿光线轨迹方程

根据DSX体系的后牛顿近似理论,直接由Lagrange方程导出了轴对称稳态时空中光子的二阶后牛顿轨迹方程,并求得在赤道平面内传播的光线偏转角.在可测量精度范围内,得到的结论与Schwarzschild和Kerr度规下的情况相吻合.     

相对论天体力学和后牛顿运动方程

叙述了与Astrod工程有关的相对论天体力学基础内容。包括相对论天体力学，广义相对论基本原理，PPN方法体系，PPN多体问题，PPN二体问题。高阶PN二体问题等。     

相对论天体力学和后牛顿运动方程

叙述了与Astrod工程有关的相对论天体力学基础内容。包括相对论天体力学、广义相对论基本原理、PPN方法体系、PPN多体问题、PPN二体问题。高阶PN二体问题等     

后牛顿近似下旋转椭球体的内外度规

在后牛顿近似下,得到由均匀不可压缩理想流体在刚体自转下形成的扁球体的内外度规．对由后牛顿效应产生的度规分量利用椭球坐标系及级数展开求得解析解．对这一具体问题,在级数展开中仅存若干项,因此结果有可能用于这一度规下粒子运动的研究．     

OJ287双黑洞轨道计算:3.5阶后牛顿近似

大质量双黑洞OJ287是一个强引力辐射源.为了探测其引力波信号,需要知道波形,而这主要是由轨道运动所决定.为此,从广义相对论3.5阶后牛顿近似的运动方程出发对OJ287的轨道进行仔细研究,取大黑洞位置固定作为近似,给出了后牛顿近似下3.5阶的次黑洞轨道解,比他人2.5阶的工作高了一阶.次黑洞撞击吸积盘面到光学爆发存在时间延迟,这对于确定轨道参数有很大影响.利用径向距离与爆发时间关系的线性模型,对最近7次爆发时刻的观测值拟合,给出了更精确的OJ287双黑洞的轨道参数及其运动轨道.分析了计算结果,研究运动特征,并且发现了两个新性质:次黑洞进动在初期增加,在晚期接近并和时,进动达到最大值,然后减小并越过0而趋于负值.尚不能确定晚期的这个行为是否由3.5阶近似不够准确所造成.运动方程中耗散性的辐射项,后牛顿2.5阶和3.5阶的系数具有相反的符号.这意味着3.5阶项反而是从外界吸收能量.但2.5阶与3.5阶之和仍然是向外辐射引力波的,体系能量变化率为负.这个工作的计算结果可以用来更精确地计算OJ287的引力辐射.     

考虑后牛顿效应的二体问题的解和星历计算

本文给出考虑后牛顿(PN)效应的二体问题解所对应的基本关系式,并仿照开普勒(Kepler)运动,给出星历表计算方法和相应的计算公式以及适用于数值研究中的简单形式。     

X射线脉冲星自主导航的光传播时间方程

详细讨论了X射线脉冲星自主导航系统的广义相对论效应,采用DSX体系的后牛顿近似方法,计算出1PN度规下的光线弯曲轨迹和时间延缓以及2PN度规下的引力延缓,得到X射线脉冲自主导航的高精度测量方程.     

双星系中两子星的自转对双星轨道变化的后牛顿效应

本文利用解摄动方程的平均值法求得在PPN框架中二体自转对轨道要素产生的后牛顿效应的长期变化影响．利用这一理论对CWCep和DRVul两颗双星中两子星的自转对轨道近星点和平近点角的长期摄动的后牛顿效应做了计算。结果表明：对于两个质量较大快速自转的子星,由此所产生的后牛顿效应的摄动量是不能忽视的。     

中心体自转对天体轨道要素变化的后牛顿效应

本文给出了在三种引力理论为中心自转对天体轨道要素变化产生的后牛顿摄动效应的研究结果。研究结果表明：六个轨道要素除长钾不受摄动影响外其它五个要素均有周期摄动，特别升交点经度和近星点经度还有长期摄动效应。最后将文中的理论结论同前人的工作做了比较还应用于行星自转对卫星轨道要素变化的摄动效应计算上。作者在文[1]中研究了天体轨道要素变化的后牛顿效应，但在该文中并没有考虑中心体自转的影响。本文研究了三种引力理论（Einstein,Brans-Dick和Nordtvedt)中的这方面效应，并给出理论和数值的研究结果。     

双星系中两子星的自转对双星轨道变化的后牛顿效应

在以前研究的基础上继续研究了双星两子星的自转对轨道变化的后牛顿效应，给出自转对轨道产生的长期摄动效应和周期摄动效应。理论结果表明，两子星的自转对轨道半长轴、轨道偏心率、近星点角和平近点经度均产生周期摄动效应，但对前两个轨道根数不产生长期摄动效,人对后两个轨道根数产生长期摄动效应，并利用理论结果对6颗双星系：EK Cep、GT Cep、NY Cep、V448 Cyg和V451 Oph中两子星的自转对轨道产生周期和长期摄动效应做了数值计算，数值结果显示：对于两个质量较大快速自转的双星系，由此产生的后牛顿铲应是不能忽视的。     

The 2nd-order Post-Newtonian Orbit Equation of Light

Based on the 2nd-order post-Newtonian approximation under the DSX frame of the general relativity theory, the 2nd-order post-Newtonian orbital equation of light in the axis-symmetrical stationary spacetime is derived, and from this, the angle of deflection of light propagating in the equatorial plane is derived. The obtained results are consistent with those of the Schwarzchild and Kerr metrics within the limits of measuring precision.     

The Orbit Computation of Binary Black Hole OJ287—A 3.5-th Order Post-Newtonian Approximation

The massive binary black hole OJ287 is a source of intense gravita- tional radiation. To detect the signal of its gravitational waves, a knowledge of the signal waveform will be of great help, and this is mainly determined by the orbital motion of the binary. For this, we carry out a detailed calculation on the orbital motion of OJ287, using the post-Newtonian (PN) approximation up to the 3.5th order within the framework of general relativity. Our result is one order higher than the previous work made by others. As in the process of radiation, there is a time delay from the instance when the secondary black hole impacts on the accretion disk of the primary to the moment of the optical outburst. This time delay has to be taken into consideration when we try to fit the calculating orbit with the observed times of outbursts. Adopting a linear relation between the time delay and the impact distance as an empirical model, we fit the cal- culating orbit with the recent 7 outbursts of OJ287, and obtain the solution of its orbital motion, as well as its averaged orbital parameters. By analyzing the result of 3.5 PN order calculation of the binary system, we find some interesting features. In the early period, the rate of precession of the secondary black hole increases, while in the late period approximate to merging, the rate of precession attains its maximum. Afterwards it diminishes, and finally becomes negative. At present we cannot determine whether this behavior is due to the insuffcient accuracy of the 3.5-th order approximation. For the term of dissipative radiation in the equation of motion, the coeffcients of the 2.5 and 3.5 PN orders possess opposite signs. This implies that the 3.5-th order term represents the absorption of energy from outside. However, the sum of the 2.5-th order and 3.5-th order terms still behaves as radiating gravitational waves outward, the rate of energy variation of the system is negative. The calculated result of this work may be useful for more accurate calculations of the gravitational radiation of OJ287.     

The Time Equation of Light Propagation in XNAV

We discuss in detail the general relativistic effect in the X-ray sourcebased navigation for autonomous position determination program (XNAV). By using the post-Newtonian approximate method of the DSX scheme, we calculate the bending of light and the gravitational time delay under the 1PN metric, as well as the gravitational time delay under the 2PN metric, and finally obtain the high-accuracy time equation of light propagation in XNAV.     

The maximum mass of neutron stars

Summary. The maximum mass of neutron stars plays an important role in determining the end point of the evolution of massive stars. As the number of stellar mass black holes in binary x-ray sources grows, and as the mass spectrum of the black holes emerges, the value of the maximum mass of neutron stars has acquired great significance. Although it is now more than sixty years since the first attempt by Oppenheimer and Volkoff, no definitive answer can be given. This review will attempt to outline the main difficulties, both conceptual as well as technical, that stand in the way of a reliable estimate of the maximum mass. We shall also highlight how laboratory experiments, as well as astronomical observations, may help to clarify the true nature of the interior of neutron stars. Received 26 November 2001 / Published online 22 April 2002     

A Solution of Einstein's Field Equations fora Tachyonic Gas: Possible Astrophysical Applications

In this paper we show that a change in the signs of some of the metric components of the solution of the field equations for the classical cosmic string results in a solution which we interpret as a time-dependent wall composed of tachyons. We show that the walls have the property of focusing the paths of particles which pass through them. As an illustration of this focusing, we demonstrate the results of a simple simulation of the interaction between one such tachyon wall and a rotating disk of point masses. This interaction leads to the temporary formation of spiral structures. These spiral structures exist for a time on the order of one galactic rotation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Differential rotation of relativistic superfluid in neutron stars

It is shown how to set up a mathematically elegant and fully relativistic superfluid model that can provide a realistic approximation (neglecting small anisotropies due to crust solidity, magnetic fields, etc., but allowing for the regions with vortex pinning) of the global structure of a rotating neutron star, in terms of just two independently moving constituents. One of these represents the differentially rotating neutron superfluid, while the other part represents the combination of all the other ingredients, including the degenerate electrons, the superfluid protons in the core, and the ions in the crust, the electromagnetic interactions of which will tend to keep them locked together in a state of approximately rigid rotation. Order of magnitude estimates are provided for relevant parameters such as the resistive drag coefficient.