未来60年的北回归线值

从回归线的概念出发，介绍并计算了未来60年的北回归线值，并对北回归线的测定方法作了介绍。     

海峡两岸的北回归线标志

笔者是广州人,是北回归线的土壤及其阳光雨露晡育我成长,使我对北回归线的文化和历史有着深厚的感情。从小爱好天文地理的我,为了探讨北回归线文化和北回归线标志的奥秘,于2005年携带GPS（全球定位系统）、相机、气压表、高度计和指南针等,计划走遍祖国大地的北回归线标志,并测量其地理三要素：纬度、经度和海拔高度。不到1年时间,     

中国的北回归线标志

在地球上的五条特殊纬线中,除北极圈外,兴建标志最多的是北回归线。这些北回归线标志,全部建在中国境内,中国的北回归线标志,形式多样,造型别致,各具特色。世界首座北回归线标志光绪三十四年（１９０８年）１０月,为庆祝台湾纵贯铁路全线通车,在台湾嘉义市西南３...     

云南墨江北回归线标志公园

云南墨江北回归线标志公园＠吴铭蟾云南墨江北回归线标志公园吴铭蟾今年６月３０日《人民日报》登刊一张照片“桂平建起北回归线标志”,文字说明是“我国第七座北回归线标志近日在广西桂平石咀镇小汶村建成,该标志是一个跨度８米、高１６米的象征地球的圆球。”我国的７座北回...     

浅说回归线漂移的天文成因

在１９９７年一年里,北回归线默然无声地南移了大约１４７米,南回归线也悄然北移了１４７米,地球的热带地区将近１０８０平方公里的疆域,其中约３３０平方公里是陆地,其余是海洋,都在无声无息中遭到了南、北温带的蚕食。１９９８年,这种蚕食还在继续,这就是所...     

科研论文微机管理软件

本文介绍了在科技工作定量管理中,利用微机对科研论文进行管理的方法,并介绍了系统结构及其功能。     

星系形成和冷暗物质模型——(Ⅱ)有偏袒的冷暗物质模型

这是文章的第二部分,介绍了冷暗物质模型和星系有偏袒形成的概念,详细介绍了N体模拟的结果和与观测的比较,并简单介绍了有关重子物质与暗物质分离过程的初步研究进展。     

2015年度国家自然科学基金天文学科常常规项目申请和资助情况分析

介绍和分析了2015年度国家自然科学基金天文学科常规项目的申请和资助情况,并介绍了2016年度天文学科资助工作的一些考虑。     

I_a型超新星爆发理论(Ⅱ):理论研究中的重要疑难问题

介绍与评述了I_a型超新星理论研究中最为突出的8个尚未解决的重要疑难问题,并简单介绍了国内围绕SNI_a开展的某些物理探讨研究．     

Ia型超新星爆发理论（II）：理论研究中的重要疑难问题

介绍与评述了Ｉａ型超新星理论研究中最为突出的８个尚未解决的重要疑难问题,并简单介绍了国内围绕ＳＮＩａ开展的某些物理探讨研究。     

On the fluid and viscoelastic deformations of the planets

The shape of the Earth and of planets depends on the exciting forces and on the rheology of the medium. From the equilibrium equation, we present the main modelisations of the viscous and inviscid fluids and we essentially describe the characteristics of linear viscoelastic deformations, for the Maxwell viscoelastic model of rheology. We use the elastic, viscoelastic and fluid Love numbers in order to investigate the associated relaxation modes. For these various kinds of rheology of the planets interior, we compute the geoid and the topography induced by an internal mass distribution. Finally, we show the importance of this viscoelastic deformation calculations in the study of the celestial body rotations.     

类星体候选者二维分布的分析

本文采用了两点相关函数方法,团分析方法(渗流方法)重度函数方法对两个类星体候选者样品进行了类星体成团性的分析。发现与Monte-Carlo无规抽样的平均结果无非常明显的差别,但显示出有尺度为100Mpc的极弱成团性。     

引力常数变化对地球自转长期变化的影响

探讨和估计了各种引力常数变化理论对地球角速度和日长变化的影响。各种引力常数变化理论包括了引力常数G随时间、空间以及速度变化等几个方面的影响。另外也估计了对地球自转角速度和日长变化产生的效应。其中有些研究对探讨地球自转变化也有启发意义。     

Possibilities of using extreme observations to estimate cometary nucleus sizes

Not considering very rare in situ measurements of cometary nuclei, observations of comets at large heliocentric distances are the only direct source of our knowledge on their sizes. Observations of a cometary nucleus in pure reflected sunlight, at the time when coma is absent, are the way in which the nucleus size can be estimated. Probabilities that extreme observations represent non—active stages of cometary nuclei and also reliability of derived cometary nucleus sizes are investigated. Statistical analysis is based on a sample of 2842 photometric observations of 67 long-period comets observed at large heliocentric distances. For any long-period comet, there is a probability of 2:3 that the sizes derived on the basis of observations at extreme distances are in good agreement with the real nucleus sizes. For new comets in Oort's sense the probability is 3:4 independent of investigated arcs of orbits. For old comets a chance to estimate correct sizes is 1:2 but on the pre-perihelion arc only 1:3. It is also demonstrated that a premature start of activity prior to perihelion or a longer fading after perihelion is more frequent than a short-time isolated activity at large heliocentric distances.     

大行星轨道运动与太阳黑子数的中长周期变化

本文对不同序列的太阳黑子数资料作了分析研究,计算得到了可能的太阳黑子活动的中长周期变化,并分别与由大行星轨道运动引起的日心轨道角动量变化的周期进行比较,发现二者具有比较一致的谱结构。基于本文的讨论和文[17]的结论,我们进一步认为大行星轨道运动是太阳黑子数周期性变化的可能的外部因素。     

Equation of state and anisotropy of pressure of magnetars

Magnetars are the neutron stars with the highest magnetic fields up to 10¹⁵–10¹⁶ G. It has been proposed that they are also responsible for a variety of extra-galactic phenomena, ranging from giant flares in nearby galaxies to fast radio bursts. Utilizing a relativistic mean field model and a variable magnetic field configuration, we investigate the effects of strong magnetic fields on the equation of state and anisotropy of pressure of magnetars. It is found that the mass and radius of low-mass magnetars are weakly enhanced under the action of the strong magnetic field, and the anisotropy of pressure can be ignored. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.     

阿昌族天文初探

阿昌族有独立的语言而没有文字,是否有传统的天文内容,过去还未有人进行发掘。我们首次从实地调查的结果得知,阿昌人中流传的对宇宙的解释,属于天文学发展初期的认识。大约从明朝改用农历后,还保留有4个传统节日和部分原始信仰。从六月火把节和十月会街节推断,其原用历法是将一年分成10个月的“十月太阳历”,两个节日是源于“十月历”的冬夏两次过新年。崇拜太阳而不崇拜月亮可作为旁证。     

The activities of comets related to their aging and origin

Two indices have been developed for the purpose of comparing the natures of various classes of comets. The first is the Activity Index (AI), measuring the inherent magnitude increase in brightness from great solar distances to maximum near perihelion. The second, or Volatility Index (VI), measures the variation in magnitude near perihelion. Tentative determinations of these two indices are derived from observations by Max Beyer over more than 30 years for long-period (L-P) and short-period (S-P) comets near perihelion and from other homogeneous sources. AI determinations are made for 32 long-period (L-P) comets and for 14 short-period (S-P). The range of values of AI is of the order of 3 to 10 magnitudes with a median about 6. An expected strong correlation with perihelion distance q, is found to vary as q ^–2.3. Residuals from a least-square solution (AI) are used for comparing comets of different orbital classes, the standard deviation of a single value of AI is only ±1^m.1 for L-P comets and ±1^m.2 for S-P comets.Among the L-P comets, 19 of period P larger than 10⁴ years yield AI = 0^m.27 ± 0^m.25 compared to 0^m.39 ± 0^m.26 for 13 of period between 10² years and 10⁴ years. This denies any fading with aging among the L-P comets. Also no systematic change with period occurs for the VI index, leading to the same conclusions. Weak correlations are found with the Gas/Dust ratio of comets. No correlations are found between the two indices, nor of either index with near-perihelion magnitudes or orbital inclination.The various data are consistent with a uniform origin for all types of comets, the nuclei being homogeneous on the large scale but quite diverse on a small scale (the order of a fraction of kilometer in extent). Small comets thus may sublimate away entirely, leaving no solid core, while huge comets may develop a less volatile core by radioactive heating and possibly become inactive like asteroids after many S-P revolutions about the Sun. When relatively new, huge comets may be quite active at great solar distances because of volatiles from the core that have refrozen in the outer layers.     

Accurate masses and radii of normal stars

Summary Binary stars are the main source of fundamental data on stellar masses and radii (M, R). Considerable progress has been made in recent years in the quality and quantity of such data, and stellar masses and radii of high accuracy have led to a number of qualitatively new and interesting results on the properties and evolution of normal stars. This paper reviews the current status of fundamentalM andR determinations which (i) have errors 2%, the limit for non-trivial results in many applications, and (ii) can be presumed valid for single stars. These two conditions limit the discussion to data fromdetached, doublelined eclipsing binary systems.After a brief discussion (Sect. 2) of the main tests for accuracy and consistency which must be met for observational data to be included in the sample, data for 45 binary systems (90 single stars) are presented in Sect. 3 (Table 1 and Figs. 2–5). Spectral types are O8-M1 on the main sequence, with only two stars clearly in the red-giant region. From the review by Popper (1980), data for only 6 systems survive unchanged in the present list, while improved data are given for 18 systems; 21 systems are new additions. Broadband colours, effective temperatures, and luminosities are also given, but are scale-dependent and considerably less reliably determined thanM andR.The observed ranges inM andR for a given colour far exceed the observational errors, primarily due to evolutionary effects within the main sequence. For this reason, single-parameter relations used to predictM andR for single stars are limited to an accuracy of some ±15% inM and ±50% inR, basically independent of the number and accuracy of the data used to establish the relations. Two-parameter calibrations are discussed (Sect. 4) which can eventually reduce these errors to & 5% in bothM andR. At this level, abundance effects become significant and presumably account for the residual scatter.Comparison of the data with stellar evolution models is the topic of Sect. 5. Characteristic features of the data which are crucial in such work are emphasized, rather than attempts to prove the validity of any particular set of models. Already fromM andR alone, some significant constraints can be derived (Fig. 4). When bothM, R, andT _e are known, the initial helium abundanceY can be estimated if the metal-abundance parameter Z is assumed or determined. Studies in which binaries with accurate values ofM, R, and Z are fit by models calculated for the precise observed masses, and withY and mixing length constrained to solar values, provide the most stringent tests of the models. Probing further model refinements such as convective overshooting requires full use of the potential of the data. For example, models may yield general main-sequence limits which are consistent with the observations, but still be unable to fit any single system to the precision of the data. Conditions for critical, informative tests are discussed. Tidal effects in binaries are briefly discussed in Sect. 6. As tidal forces are extremely sensitive to the dimensions and internal structure of the stars, the present sample is well suited for such studies. Recent success in matching computed and observed apsidal-motion parameters for early-type binaries is mentioned. Finally, main priorities for future work are outlined.     

Heating of coronal arcade by a slow motion of its footpoints

In their “mixing time” theory of magnetic heating of the corona by slow photospheric motion, Heyvaerts and Priest (1984) neglected certain second-order terms in the calculation of the energy and retained the linear part of the perturbed magnetic field which led to infinite displacements. In this paper, we revised these points. Our main results are: (1) the heating efficiency we obtained is greater than what they found. (2) Dissipation-free, linear evolution of the force-free field of coronal arcade is impossible. (3) The possibility of reconnection of field lines of non-linear force-free field is clarified in terms of the field configuration and it is pointed out that reconnection is most likely at a height equal to about one width of the arcade.