多种资料综合处理的精度分析和相对权因子

在统计轨道理论的框架下分析多种技术资料的综合处理方法的精度．提出除了拟合剩余残差的ＲＭＳ外,皮尔逊（Ｐｅａｒｓｏｎ） χ２ 统计量和高阶矩也应作为判断解算好坏的重要指标．初步探讨了利用这些统计量评价不同技术间的相对权因子给定问题．作为对系统差来源的初步探索,利用考察协方差分析理论分析了考察参数误差对解算的影响,讨论了考察协方差与相对权因子的关系     

人类对木星大气的首次直接考察

人类对木星大气的首次直接考察陈丹在木星探测史上，１９９５年１２月７日是非常重要的值得纪念的日子，人类第一个探测器于是日冲入木星大气层，实现了对木星大气的首次直接考察，所取得的观测资料的质量超乎科学家的最乐观的估计，促使科学家重新考虑木星及至太阳系构成...     

云南天文台观测到的黑子本影点

本文报道了国内首次对黑子本影细节的直接照相观测。通过对这些本影细节的形态的考察和对它们的平均视大小的粗略估计,认为其中一些是本影点。本文还讨论了它们与黑子发展演化过程的关系及其它有关问题。     

寻找南极陨石

人类历史上在南极之外的各大陆发现或找到的陨石非常有限……以日本和美国为首的世界各国考察队在南极展开了寻找陨石活动……我国极地考察办公室于2002年成立了专门寻找陨石的格罗夫山考察小分队……我国考察工作共回收陨石总数4448块,已成为拥有南极陨石最多的国家之一……     

CAPS（Covariance Analysis Program Developed at Shanghai Observatory）的原理、结构和使用

推导了在Givens-Gentleman正交变换形式下的考察协方差分析理论,给出一些重要的统计量,如考察协方差矩阵、摄动矩阵等在此形式下的表达式。在理论分析的基础上给出编写CAPS时采用的详细流程图,并介绍在使用CAPS时应注意的一些问题。     

国外空间探测器发展概览（上）

空间探测器的问世使人类可以近距离探测地外星球,甚至就地考察、取样返回、载人登陆,从而获得了大量有用信息。例如,进一步揭示地球、生命乃至太阳系的起源和演变：掌握太阳系内一些重要地外星球上的生命、地质、气候、重力、环境等,这对人类的科技发展和未来生存具有重要的长远意义。目前,全球已发射了多种空间探测器,它们相继考察了月球、水星、金丛、火星、木星、土星、天王星、海王星、小行星和彗星等,并将探测冥王星。     

一米望远镜卡焦照相装置的星等系统——云台一米望远镜卡焦照相测光性能研究

本文总结了用实测方法考察云台一米望远镜卡焦照相装置星等系统的结果,得出了本仪器系统与U、B、V系统之间的转化方程,并对它们的适用范围进行了讨论,为在一米镜上进行照相测光工作提供了一个依据。     

关于HD94033的双星假设

在1981年2月至1984年4月间,我们对矮造父变星HD94033进行了4个观测期的观测。综合考察跨度为10年的观测资料,我们发现了它的O-C随周数的规律性变化。在研究了这种变化后,我们得到HD94033可能是一个双星系统的结论。     

DA型和非DA型白矮星的目视表面亮度和半径的关系

本文验证了恒星目视表面亮度参数Fv与色指数（V－I）之间的单值关系并将其应用于白矮星半径测定研究，对68颗白矮星求得了平均线半径为0.0103R⊙；在对DA型和非DA型白矮星的关分别进行考察中发现：平均来说，非DA型白矮星的线半径比DA型白矮星小12％左右。     

宇宙信息

宇宙信息星系研究的新进展今天天文学家利用空间望远镜已经较为深入地考察了年龄在１００～１５０亿年的宇宙。虽然宇宙微波背景图提供了宇宙幼年时期的一幅模糊图象，然而天文学家对星系是在什么时候和怎样形成的仍感困惑。星系演化难题中的一个关键部分已经通过《哈勃深...     

Kinetic equilibrium of nonlinear electromagnetic waves in electron-positron-ion magnetoplasmas

The problem of a one-dimensional, nonlinear, circularly polarized wave in a collisionless plasma is solved for the case in which the group velocity of the localized wave is zero relative to the plasma frame.For an electron-positron plasma the ponderomotive potential is repulsive, and both small and large amplitude waves in the presence of reflected and transmitted particles is discussed.The inclusion of an external magnetic field such that the cyclotron frequency is smaller than the wave frequency does not alter qualitatively the results of the fieldless case, except for the fact that an electrostatic potential is generated.For the case in which the cyclotron frequency is larger than the wave frequency, the resulting potential is attractive, and it is shown that no localized waves can coexist with confined and transmitted particles. If, however, an ionic component is presnt in the electron-positron plasma, such as may be the case in pulsar magnetospheres, localized waves may again be possible.     

Rotational modes in a slowly and uniformly rotating star

A perturbation method is derived forr-modes in a slowly and uniformly rotating star. In contrast to previous studies, the perturbation of the gravitational potential is included in the perturbation method.On the assumption that the effects of the centrifugal force are taken into account in the equilibrium model up to the second order in the angular velocity, an eigenvalue problem of sixth-order in the radial coordinate is derived that allows one to determine the zeroth-order toroidal displacement field and the third-order term in the expansion of the eigenfrequency. Furthermore, another eigenvalue problem is derived that governs the first-order toroidal displacement field and the fourth-order term in the expansion of the eigenfrequency. This second eigenvalue problem is also of the sixth-order in the radial coordinate.It is shown that the third-order term in the expansion of the eigenfrequency is real, and that the fourth-order term is zero.     

Self-consistent electromagnetic field in a nearly co-rotating magnetosphere

An example of the self-consistent solution which belongs to the non-trivial solution, obtained in a previous paper (Kaburaki, 1985), is found in a nearly co-rotating inner magnetosphere. Though the stellar wind is neglected there compared with the co-rotatinal velocity, drift motion around the magnetic axis, which is a manifestation of inertial effects, is determined self-consistently with the electromagnetic field. In this process, explicit expressions for the energy integral in the rotating frame and for the density distribution are also obtained. These expressions contain a fundamental length, which is to be evaluated according to physical conditions of a magnetosphere and determines the asymptotic-kinetic energy of a plasma particle at infinity. The electric current associated with the drift motion is too small to alter the original magnetic field, but the electric field is modified by the inertial effects even in the inner magnetosphere. The integrated Ohm's law is used to describe a force balance in the rotating frame, in the limits of weak and strong magnetic field.     

Classification of Stellar Spectra with Fuzzy Minimum Within-Class Support Vector Machine

Classification is one of the important tasks in astronomy, especially in spectra analysis. Support Vector Machine (SVM) is a typical classification method, which is widely used in spectra classification. Although it performs well in practice, its classification accuracies can not be greatly improved because of two limitations. One is it does not take the distribution of the classes into consideration. The other is it is sensitive to noise. In order to solve the above problems, inspired by the maximization of the Fisher’s Discriminant Analysis (FDA) and the SVM separability constraints, fuzzy minimum within-class support vector machine (FMWSVM) is proposed in this paper. In FMWSVM, the distribution of the classes is reflected by the within-class scatter in FDA and the fuzzy membership function is introduced to decrease the influence of the noise. The comparative experiments with SVM on the SDSS datasets verify the effectiveness of the proposed classifier FMWSVM.     

SOUSA: the Swift Optical/Ultraviolet Supernova Archive

This paper studies the motion of an infinitesimal mass in the framework of Robe’s circular restricted three-body problem in two cases; the first case is when the hydrostatic equilibrium figure of the first primary is an oblate spheroid, the shape of the second primary is considered as an oblate spheroid with oblateness coefficients up to the second zonal harmonic, while the first primary is a Roche ellipsoid in the second case and the full buoyancy of the fluid is taken into account. In case one; it is observed that there are two axial libration points on the line joining the centres of the primaries, points on the circle within the first primary are also libration points under certain conditions. It is further found that the first axial point is stable, while the second one is conditionally stable, and the circular points are unstable. It is found in case two that there is exist only one libration point (0,0,0) this point is stable.     

The short timescale bursts of Cyg X-1 in the high and transitional states

Short timescale bursts or “shots” of Cyg X-1 in one ms time bins were obtained from PCA/RXTE observation. By superposing many shots lined up at the peak, a mean profile was obtained, and this was done seperately for the different states, high, transitional and low. The mean shot profile is different for the different states. The duration of shot is shorter in the high than in the transitional state. In both, the duration is about 0.11 s, which is shorter than in the low state. The profile is more asymmetrical in high than in low energy bands. In the transitional state, the average hardness during shots is lower than that of the steady component. The mechanism of shot generation is discussed.     

Cosmological models reconstructed from jerk: A thermodynamic analysis

The thermodynamic viability of some dark energy models reconstructed through the cosmological jerk parameter is investigated. Some models, already available in the literature, are picked up for the purpose. The models are broadly classified in two categories, depending on whether there is an interaction in the dark sector or not. The validity of the Generalized Second law of Thermodynamics (GSL) is used as the diagnostics. Hayward–Kodama temperature is considered in place of Hawking temperature in order to account for the dynamical nature of the spacetime. It is found that depending on the parametrization ansatz for jerk, the total entropy is increasing with time, so it is quite possible to find viable models. This holds even with an interaction in the dark sector.     

Evidence for objects of lunar mass in the early solar system and for capture as a general process for the origin of satellites

The problem of the accumulation of the Moon is discussed on the assumption that the Moon is a captured object. If it is such, it is highly improbable that it is the only object of this kind present in the early solar system. Evidence indicating that other massive objects were present at that time is presented. Also, it is pointed out that the interior of the Moon must contain normal solar proportions of the elements of intermediate volatility in the lunar interior, if the Moon accumulated in a gas sphere.     

57-second oscillations in Nova Centauri 1986 (V842 Cen)

High-speed photometry in 2008 shows that the light curve of V842 Cen possesses a coherent modulation at 56.825 s, with sidebands at 56.598 and 57.054 s. These have appeared since this nova remnant was observed in 2000 and 2002. We deduce that the dominant signal is the rotation period of the white dwarf primary and the sidebands are caused by reprocessing from a surface moving with an orbital period of 3.94 h. Thus, V842 Cen is an intermediate polar (IP) of the DQ Herculis subclass, is the fastest rotating white dwarf among the IPs and is the third fastest known in a cataclysmic variable. As in other IPs, we see no dwarf nova oscillations, but there are often quasi-periodic oscillations in the range 350–1500 s. There is a strong brightness modulation with a period of 3.78 h, which we attribute to negative superhumps, and there is an even stronger signal at 2.886 h which is of unknown origin but is probably a further example of that seen in GW Lib and some other systems. We used the Swift satellite to observe V842 Cen in the ultraviolet and in X-rays, although no periodic modulation was detected in the short observations. The X-ray luminosity of this object appears to be much lower than that of other IPs in which the accretion region is directly visible.     

Magnetogravitational stability of self-gravitating plasma with thermal conduction and finite Larmor radius through porous medium

The problem of incipient fragmentation of interstellar matter to form condensation is investigated taking into account the porosity, viscosity, thermal conductivity, and effect of finite ion-Larmor radius (FLR) on the self-gravitating plasma having a uniform magnetic field acting in vertical direction. Relevant linearized equations are stated and dispersion relation is obtained. Wave propagation in longitudinal and transverse direction to the magnetic field is considered. Stability and instability of the medium is discussed. It is found that if the Jeans's instability condition is not fulfilled the medium must remain stable. Magnetic field, FLR and porosity do not affect the Jeans's criterion of instability in longitudinal direction but in transverse direction, the magnetic field and FLR have stabilizing effect which is reduced due to porosity of the medium. Thermal conductivity destabilizes the medium in both the directions. In transverse direction contribution of FLR on the Jeans's expression for instability is not observed in thermally conducting medium.