行星磁场与卫星引力及其相对运动的统计关系

从知识某些天体具有磁场起，人们就对其磁场的起源提出了种种解释，例如有电池说，转子说，公石说，发电机说等等。但由于这些学说都分别与某些观测事实相抵触而未被公认，因此星球磁场的起源一直是未能解决的命题。余先河先生提出，星球的磁场起源可能与所受的引力有关，行星的磁场强度正比于其所受卫星的引力，正比于卫星与行星的引力连线转动的相对角速度。本文对这两方面的命题分别进行了相关分析，得到其相关系数分别为：ｒ＝０     

太阳硬X射线爆发与行星际质子流量的统计关系

本文根据１９８０年２月至１９８９年１１月期间ＳＭＭ卫星的硬Ｘ射线（ＨＸＲ）暴观测和ＧＯＥＳ卫星的行星际质子积分流量观测，证认出４８个共同样品，统计发现ＨＸＲ暴的寿命Ｔｄ（ｓ）、峰值记数率Ｆｘ（ｃ／ｓ）和爆发期间发射的总光子数ｃ的对数值，与行星际质子积分流量（被归一到耀斑本地）值Ｆｐ的对数值之间，均具有特别显著的线性关系，其中以ｌｏｇＦｐ与ｌｏｇＣ的线性关系为最好，其拟合方程是ｌｏｇＦｐ（＞１０ＭｅＶ）＝一０．６０４＋０．５３８ｌｏｇＣ，相关系数ｒ为０．７０，相对标准误差为０．２８．文中对质子积分流量的预测精度也作了讨论，并给出了置信区间。     

银河系的星际磁场

银河系的星际磁场许梅观测证据从月球到太阳，从恒星到星云，都具有强度不等、性质各异的磁场。现已测知地球的磁场强度约为０．ＳＧ（高斯），水星、火星的场强分别为４００Ｙ和６０Ｙ（伽玛，Ｉｙ一１０－’Ｇ），诸行星中木星最大，其磁场也最强，约为１２Ｇ。太阳的平...     

太阳硬X射线爆发行星际质子流量的统计关系

本文根据１９８０年２月至１９８９年１１月期间ＳＭＭ卫星的硬Ｘ射线暴观测和ＧＯＥＲ卫星珠卫星际质子积分流量Ｆｐ观测，证认出４８个共同样品，统计发现ＨＸＲ暴的寿命ＴＤ，峰值记数率Ｆｘ和爆发期间射的总光子数Ｃ的对数值，与行星际质子积分流量（初归一到耀斑本地）值Ｆｐ的对数值之间，均具有特别显著的线性关系，其中以ｌｏｇＦｐ与ｌｏｇＣ的线性关系的最好，其拟合方程是ｌｏｇＦｐ＝－６．０４＋０．５３８ｌｏｇＣ，相     

行星摄动力对太阳活动的调制

本文采用天体力学方法，考虑太阳系九大行星对太阳表面局部区域的摄动力，建立了太阳表面受行星起潮力的数值计算模型．利用此模型，针对历史上发生的100个大太阳耀斑事件，计算各耀斑区耀斑发生前后所受行星起潮力的变化．从耀斑发生的时间分布统计得到：在100个耀斑中，有75个耀斑发生在行星综合起潮力合力极大前后三天内．证明行星摄动对太阳活动有调制作用．最后，本文还对太阳活动起源、活动周期等问题进行了简要的讨论．     

《大气一号》气球卫星轨道倾角变化分析

引起《大气一号》两颗气球卫星（ＤＱ－１Ａ和ＤＱ－１Ｂ）轨道倾角变化的摄动因素主要是太阳光压摄动、大气旋转和日月引力摄动。太阳光压摄动引起气球卫星轨道倾角增大，平均每天变化约０．００１７，大气旋转引起轨道倾角减小，平均每天变化不到０．０００１，但随着高度下降，变化量亦增大，陨落前达０．００２。本文根据卫星轨道摄动理论，给出气球卫星轨道倾角变化的一种定量分析方法，得到的分析结果为：（１）由太阳光压摄动     

太阳黑子数R_Y和R_L的稳定性分析

黑子数用国际系统ＲＩ作标准，与云南天文台ＲＹ、国内联合ＲＬ比较，分别求出总平均值：ｑ（Ｙ）＝０．９３００４±０．００４７２，ｑ（Ｌ）＝０．９１４０９±０．００４４４。这是后者删除“偶然误差”次数多于前者的结果。对国内联合数据的处理，应以一个观测点为准，以此归算作补充的部分数据，才有可能使数据系列保持相对的稳定     

MOND理论和暗物质模型的检验

从理论上探讨在地球引力系统内，修正动力学的引力理论以及暗物质模型的预言．着重研究修正动力学(MOND)的引力理论中一些常用的模型，对其中一个最简单模型，给出了球对称情况下引力势的一般表达式，计算了地球引力场中这些模型预言的卫星角速度，发现不同模型给出的角速度是不相同的，并且将这些值分别与牛顿理论的角速度值相比较．虽然这些模型的角速度与牛顿理论角速度的差异都很小，但简单模型的差异更大一些．对于月球作为卫星的情况，目前的技术有可能对这个角速度差进行实际观测．最后估算暗物质模型中月球绕地球运动角速度所受到的影响，证明它远远小于MOND理论的效应．由此对这个角速度差的观测，就构成检验MOND理论与暗物质模型的一个判据．     

活动星系核红移分布中的准周期峰

本文作者在活动星系核红移分布（０＜ｚ≤０．２）中发现了准周期性的峰。这些峰分布于ｚ≈０．０３０，０．０６０，０．０９０，０．１２０处（其中ｚ＝０．０６０处的峰是１９６８年Ｂｕｒｂｉｄｇｅ发现的并于１９９０年证实）。红移数据的功率谱表明。这些峰值的准周期为△ｚ＝０．０２７±０．００２。两个相邻的峰所表征的空间距离为８１±６ｈ~（－１）Ｍｐｃ。这可能是宇宙大尺度结构中各个单元的特征尺度（Ｈ_０＝１００ｈ~（－１）Ｍｐｃ~（－１）ｍｓ~（－１）。     

星际水脉泽源中高速气体的CO巡测

用射电天文联合实验室紫金山天文台青海站１３．７米望远镜，于１９９７年４月对９７个水脉泽源做了ＣＯ（Ｊ＝１－０）的巡测及部分成图观测，结果表明８１个源的谱线适于作成协星体活动分析．经初步证认有外向流候选者３３个，全部为首次给出高速范围．对其轮廓特点及与Ｈ２Ｏ脉泽辐射的关系作了简要讨论．ＣＯ高速气体和Ｈ２Ｏ脉泽的速度范围和峰值速度在多数情况下分别相符，这说明两者的激发可能相关．     

Analytical Estimation of the Scale of Earth-Like Planetary Magnetic Fields

In this paper we analytically estimate the magnetic field scale of planets with physical core conditions similar to that of Earth from a statistical physics point of view. We evaluate the magnetic field on the basis of the physical parameters of the center of the planet, such as density, temperature, and core size. We look at the contribution of the Seebeck effect on the magnetic field, showing that a thermally induced electrical current can exist in a rotating fluid sphere. We apply our calculations to Earth, where the currents would be driven by the temperature difference at the outer-inner core boundary, Jupiter and the Jupiter’s satellite Ganymede. In each case we show that the thermal generation of currents leads to a magnetic field scale comparable to the observed fields of the considered celestial bodies.     

Analysis of the potential field and equilibrium points of irregular-shaped minor celestial bodies

The equilibrium points of the gravitational potential field of minor celestial bodies, including asteroids, comets, and irregular satellites of planets, are studied. In order to understand better the orbital dynamics of massless particles moving near celestial minor bodies and their internal structure, both internal and external equilibrium points of the potential field of the body are analyzed. In this paper, the location and stability of the equilibrium points of 23 minor celestial bodies are presented. In addition, the contour plots of the gravitational effective potential of these minor bodies are used to point out the differences between them. Furthermore, stability and topological classifications of equilibrium points are discussed, which clearly illustrate the topological structure near the equilibrium points and help to have an insight into the orbital dynamics around the irregular-shaped minor celestial bodies. The results obtained here show that there is at least one equilibrium point in the potential field of a minor celestial body, and the number of equilibrium points could be one, five, seven, and nine, which are all odd integers. It is found that for some irregular-shaped celestial bodies, there are more than four equilibrium points outside the bodies while for some others there are no external equilibrium points. If a celestial body has one equilibrium point inside the body, this one is more likely linearly stable.     

Research career of an astronomer who has studied celestial mechanics

Celestial mechanics has been a classical field of astronomy. Only a few astronomers were in this field and not so many papers on this subject had been published during the first half of the 20 thcentury.However, as the beauty of classical dynamics and celestial mechanics attracted me very much, I decided to take celestial mechanics as my research subject and entered university, where a very famous professor of celestial mechanics was a member of the faculty. Then as artificial satellites were launched starting from October 1958, new topics were investigated in the field of celestial mechanics. Moreover, planetary rings,asteroids with moderate values of eccentricity, inclination and so on have become new fields of celestial mechanics. In fact I have tried to solve such problems in an analytical way. Finally, to understand what gravitation is I joined the TAMA300 gravitational wave detector group.     

Dynamo action in an ambient field

The origin of global magnetic fields in celestial bodies is generally ascribed to dynamo action by fluid motions in their electrically conducting interiors. Some objects – e.g. close‐in extra‐solar planets or the moons of some giant planets – are embedded in ambient magnetic fields which modify the generation of the internal field in these bodies. Recently, the feedback of the magnetospheric field by Chapman‐Ferraro currents in the magnetopause onto the interior dynamo has been proposed to explain the observed weakness of the intrinsic magnetic field of planet Mercury. We study a simplified mean‐field dynamo model which allows us to analytically address various issues like positive and negative feedback situations, stationary versus time‐dependent solutions, and the stability of weak and strong field branches. We discuss the influence of the response function on the solutions when the external field depends on the strength of the intrinsic field like in the situation of the feedback dynamo of Mercury. We find that the feedback mechanism works only for a narrow range of dynamo numbers in the case of Mercury which makes him unique in our solar system. We conclude with some implications for extra‐solar planets (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Post-post-Newtonian Amendments of Radar Echo Delay Test in Reissner-Nordström Field

Starting from the differential equation of motion of photons on equatorial plane and in spherically symmetric field of gravitation and adopting the post-Newtonian approximate method, the post-post-Newtonian amendments of radar echo delay test in the Reissner-Nordström metric field are investigated. Via calculations the post-Newtionian and post-post-Newtonian amendments are obtained. When the electric charge Q is equal to zero, these results are applicable to electrically neutral celestial bodies, and the amendments of post-Newtonian parts are consistent with those provided by classical literature. The approximate expansion used in this paper can also be adopted to probe the amendments of still higher orders. The high-order amendments for radar echo have important significance to the ongoing high-precision spatial gravitation tests.     

Magnetic field in a fluctuating <Emphasis Type="Italic">ABC</Emphasis> flow

The standard dynamo models that explain the origin of the large-scale magnetic fields of celestial bodies are related to the view of turbulent or convective flows as a locally statistically homogeneous and isotropic, but not mirror-symmetric, random field. Using an ABC flow, which is a classical example of a flow with deterministic chaos, we ascertain the extent to which the behavior of the magnetic field in such a flow is similar to the behavior of the magnetic field in mirror-asymmetric turbulence. Such a similarity has been found to be achieved if its coefficients A, B, and C are assumed to be random processes.     

Evidence for cyclotron maser emission from the Sun and stars

In recent years radiation has been observed from planets, Sun and stars that is best explained by the cyclotron maser instability; in fact, all celestial bodies that might feasibly emit and be detected by their cyclotron maser radiation have been detected. Here we review those observations, the developments in the theory, the recent work on the effiency of energy transfer by cyclotron maser radiation, and some recent and future observations that might demonstrate whether the mechanism is energetically important in solar and stellar flares.

     

The libration points of axisymmetric satellite in the gravitation field of two triaxial rigid bodies

In this paper we consider the restricted problem of three rigid bodies (an axisymmetric satellite in the gravitation field of two triaxial primaries). The collinear and triangular equilibrium solutions are obtained. The effect of the primaries on the location of the libration points of a spherical satellite has been studied numerically.     

Stellar dynamics

This review attempts to place stellar dynamics in relation to other dynamical fields and to describe some of its important techniques and present-day problems. Stellar dynamics has some parallels, in increasing order of closeness, with celestial mechanics, statistical mechanics, kinetic theory, and plasma theory; but even in the last case the parallels are not very close. Stellar dynamics describes, usually through distribution functions, the motions of a large number of bodies as they all act on each other gravitationally. To a good approximation each star can be considered to move in the smoothed-out field of all the others, with random encounters between pairs of stars adding a slow statistical change to these smooth motions. Smooth-field dynamics has a well-developed theory, and the state of smooth stellar systems can be described in some detail. The ‘third integral’ presents an outstanding problem, however. Stellar encounters also have a well-developed theory, but close encounters and encounters of a single star with a binary pose serious problems for the statistical treatment. Star-cluster dynamics can be approached through a theory of smooth-field dynamics plus changes due to encounters, or alternatively through numerical simulations. The relation between the two methods is not yet close enough. The dynamical evolution of star clusters is still not fully understood.     

Some aspects of rotational and magnetic energies for a hierarchy of celestial objects

Celestial objects, from earth like planets to clusters of galaxies, possess angular momentum and magnetic fields. Here we compare the rotational and magnetic energies of a whole range of these celestial objects together with their gravitational self energies and find a number of interesting relationships. The celestial objects, due to their magnetic fields, also posses magnetic moments. The ratio of magnetic moments of these objects with the nuclear magnetic moments also exhibits interesting trends. We also compare their gyromagnetic ratio which appears to fall in a very narrow range for the entire hierarchy of objects. Here we try to understand the physical aspects implied by these observations and the origin of these properties in such a wide range of celestial objects, spanning some twenty orders in mass, magnetic field and other parameters.