星爆后星系NGC4736核区的环状结构

在１９９２年３月３１日至４月２日期间，我们利用云南天台１ｍ望远镜２号ＣＣＤ和缩焦装置，对环星系ＮＧＣ４７３６进行了Ｖ和Ｉ波段深曝光观测。在经过Ｒｉｃｈａｒｄｓｏｎ－Ｌｕｃｙ图象复原以及自适应滤波两种方法处理后，发现仅仅在Ｖ波段图像上，其核区存在一个直径约为１０″的环状结构。     

2.16m望远镜卡焦平面星象位置的模拟及其在光纤定位观测中的应用

本文利用GSC和SAO星表以及2.16m望远镜底片上星象位置的xy测量值,分析了该望远镜卡焦平面上星象位置的误差分布,提出了改正解析表达式.利用SUN工作站计算打印出了适合多目标光纤系统光纤探头定位用的纸质观测机场星图,代替采用照相底片作多纤维观测的视场模板,取得了满意的观测效果提高了工作效率.     

1.56m望远镜CCD照相机系统的消光系数和转换系数测定

测定了1.56m望远镜CCD照相机系统的消光系数和转换系数，消光系数k′和k″列在表1和表2，从观测星等到标准星等的转换系数列在表3，结果表明1.56m望远镜CCD测光系数做绝对测光是有困难的，最好是做相对测光。     

兴隆60 cm望远镜主焦CCD系统测光性能的研究

对兴隆６０ｃｍ望远镜主焦ＣＣＤ系统的测光性能进行了测试和研究．测定了ＣＣＤ快门时间函数,讨论了快门延迟效应对短时间曝光观测的可能影响．通过观测大批Ｌａｎｄｏｌｔ标准星,较准确地定出了ＢＶＲＩ宽带测光的星等系统转换关系,结果表明本系统与标准ＢＶＲＩ系统很接近．对ＣＣＤ系统的天文测光精度作了仔细的检验和分析,并对ＰＳＦ拟合测光和孔径测光两种方法进行了比较     

观测过程中较差大气折射引起的星象移动的计算和研究

本文给出了一种计算观测过程中较差大气折射引起的星象移动的方法，包括焦面最佳转动的确定．算法中除大气折射公式外，都是严格的．本文用这种方法详细计算了我国即将研制的大天区面积多目标光纤光谱望远镜（ＬＡＭＯＳＴ）中较差大气折射引起的星象移动，文中详细计算了望远镜安放在纬度４０．４°，观测天区－１０°δ＋９０°，天体过子午圈前后１．５小时，视场直径５°情况下，星象移动的结果，并得到星象的最大位移为０．８５９″，ＬＡＭＯＳＴ中光纤的直径是３．３″，光纤定位系统可不作校正．本文提出了实现焦面最佳转动的导星方法：在导星元件是ＣＣＤ的情况下，可任选一颗星来引导焦面旋转，只要使星象在ＣＣＤ靶面上作切向位移，其值等于按本文方法计算得到的值，若采用赤径、赤纬分角线方向（四个４５°方向）的星来引导旋转，也可近似地得到焦面的最佳转动．本文提出的算法和导星方法，可应用于任何天区，任意的观测时间和任何形式的焦面可旋转的望远镜．     

射电源0716 714和0839 187的光学定位

利用北京天文台具有ＣＣＤ终端的６０ｃｍ光学望远镜（Ｖ波段）观测射电源的光学对应体，得到了０７１６＋７１４和０８３９＋１８７精确的光学位置。参考星表采用拉帕尔玛（ＬａＰａｌｍａ）的１８ｃｍ全自动子午环观测资料编制的ＣＡＭＣ星表，该星表是ＦＫ５星表系统。两颗源位置的内符精度约为０．″１９，与其他作者给出的光学和射电位置观测结果分别进行了比较     

Compton γ射线望远镜的直接解调成像

Ｃｏｍｐｔｏｎγ射线望远镜ＣＯＭＰＴＥＬ／ＣＧＲＯ工作于０．７５－３０ＭｅＶ能区，本文应用直接解调方法分析ＣＧＲＯ＃１观测的ＣＯＭＰＴＥＬ数据，准确定出Ｃｒａｂγ射线源的位置，在１０－３０ＭｅＶ能区，分辨开最大似然法所不能完全分辨的Ｃｒａｂγ射线源和类星体ＰＫＳ０５２８＋１３４，得出优于传统成像方法所得的成像结果．应用直接成像方法处理γ射线脉冲星Ｇｅｍｉｎｇａ分位相数据，发现Ｇｅｍｉｎｇａ在１０－３０ＭｅＶ能区仍存在辐射，辐射集中在Ｇｅｍｉｎｇａ第一个峰的位相区域．结果表明，应用直接解调方法对Ｃｏｍｐｔｏｎ望远镜数据作成像分析是完全可行的     

星爆后星系NGC4736核区的环状结构

在１９９２年３月３１日至４月２日期间，我们利用云南天文台１ｍ望远镜２号ＣＣＤ和缩焦装置，对环星系ＮＧＣ４７３６进行了Ⅴ和Ⅰ波段深曝光观测。在经过Ｒｉｃｈａｒｄｓｏｎ－Ｌｕｃｙ图象复原以及自适应滤波两种方法处理后，发现仅仅在Ⅴ波段图象上，其核区存在一个直径约为１０″的环状结构。     

用佘山40厘米折射望远镜测定的恒星三角视差总览

对于用佘山40厘米折射望远镜拍摄的10组底片，用底片常数法和中心重叠法分别重新作了归算；对于饮食大时角底片的组，归算中使用在恒星常数中加进折射项的办法计入了大气色散改正。给出了15颗星的相对视和自行，以及由重叠解换算的绝对视差，对视差测定值的精度作了讨论。     

Comptonγ射线望远镜的直接解调成像

Ｃｏｍｐｔｏｎγ射线望远镜ＣＯＭＰＴＥＬ／ＣＧＲＯ工作于０．７５－３０ＭｅＶ能区，本应用直接解调方法分析了ＣＧＲＯ＃１观测的ＣＯＭＰＴＥＬ数据，准确定出Ｃａｒａｂγ射线源的位置，在１０－３０ＭｅＶ能区，分辨开最大似然法所不能完全分辨的Ｃｒａｂγ射线源和类星体ＰＫＳ０５２８＋１３４，得出优于传统成像方法所得的成像结果。     

A survey of orbits of co-orbitals of Mars

Many asteroids with a semimajor axis close to that of Mars have been discovered in the last several years. Potentially some of these could be in 1:1 resonance with Mars, much as are the classic Trojan asteroids with Jupiter, and its lesser-known horseshoe companions with Earth. In the 1990s, two Trojan companions of Mars, 5261 Eureka and 1998 VF₃₁, were discovered, librating about the L₅ Lagrange point, 60° behind Mars in its orbit. Although several other potential Mars Trojans have been identified, our orbital calculations show only one other known asteroid, 1999 UJ₇, to be a Trojan, associated with the L₄ Lagrange point, 60° ahead of Mars in its orbit. We further find that asteroid 36017 (1999 ND₄₃) is a horseshoe librator, alternating with periods of Trojan motion. This asteroid makes repeated close approaches to Earth and has a chaotic orbit whose behavior can be confidently predicted for less than 3000 years. We identify two objects, 2001 HW₁₅ and 2000 TG₂, within the resonant region capable of undergoing what we designate “circulation transition”, in which objects can pass between circulation outside the orbit of Mars and circulation inside it, or vice versa. The eccentricity of the orbit of Mars appears to play an important role in circulation transition and in horseshoe motion. Based on the orbits and on spectroscopic data, the Trojan asteroids of Mars may be primordial bodies, while some co-orbital bodies may be in a temporary state of motion.     

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.     

Estimation of the Time Scale of Merging of the Components of Contact Binaries of the W UMa Type

Time scales of the transition from contact binary systems of the W UMa type to single stars of the blue straggler type are estimated. A model of one-way mass transfer from the primary component to the companion inside a common envelope (Eggen et al.) and a model of a contact binary lying on the zero-age main sequence with a companion that is losing mass (F. van't Veer) are used to calculate these scales. The merging times of components were calculated for 304 contact systems of the W UMa type from the Catalog of Approximate Photometric and Absolute Elements of Eclipsing Variable Stars on a scale of loss of mass and orbital angular momentum due to magnetic braking, under the assumption of synchronization of the axial rotation and orbital revolution. On the basis of the resulting statistics, the characteristic merging scales are 0.4-0.6 and 0.5-0.7 Gyr, respectively, for the above two models. The results of a comparison with the work of other authors are discussed.     

淮河洪水的可公度性分析

分析了上两个世纪发生在淮河的洪水事件的可公度性，根据其可公度值及其黄金分割点指出1991年与2003年淮河洪水的不可避免，最后讨论了可公度性的局限及淮河洪水可公度值的可能机制。     

Flattening of galaxies of different morphological types in subclusters of Coma

This paper deals with the observed variation in the flattening of galaxies with the density of galaxies in the subclusters of Coma surrounding NGC 4889, NGC 4874, and NGC 4839 based on data from the Abastumani Combined Catalog of Galaxies. The mean values of the observed ratios of the diameters of the galaxies, as well as histograms of their distributions, indicate that in the central, dense regions of the subclusters within a volume of 0.5h ₇₅ ⁻¹ Mpc³, E and S0 type galaxies are close to spheroidal. A significant reduction in the mean values of the diameters of the galaxies in the subclusters is noted, regardless of their morphology relative to the galaxies in the halo of the Coma cluster. In the subclusters, spiral galaxies are found with a hydrogen deficit that is more than 5 times the hydrogen deficit in spirals within the halo of the cluster. According to their 3-D coordinates, most of the galaxies with a hydrogen deficit are located closer to the south-east edge of the subcluster surrounding NGC 4874 near an extended gas filament in the x-ray region. This may indicate that the subcluster is moving toward a central condensation of faint galaxies in the Coma cluster and a possible merger with it. __________ Translated from Astrofizika, Vol. 50, No. 3, pp. 355–368 (August 2007).     

基于STK的寿命末期GEO卫星轨道演化分析

地球同步轨道上的GEO卫星接近寿命末期时,星上的有效载荷和电子元器件等仍能正常应用,此时如果只做东西方向的位置保持,可以大幅度延长卫星的在轨工作寿命。简要介绍了引起GEO卫星轨道变化的主要摄动力,利用STK软件分析寿命末期GEO卫星的运动规律,并给出这类GEO卫星轨道演化的仿真分析流程,用以指导寿命末期GEO卫星的开发应用工作。     

The discovery of Segue 2: a prototype of the population of satellites of satellites

We announce the discovery of a new Milky Way satellite Segue 2 found in the data of the Sloan Extension for Galactic Understanding and Exploration (SEGUE). We followed this up with deeper imaging and spectroscopy on the Multiple Mirror Telescope (MMT). From this, we derive a luminosity of   M _v =−2.5  , a half-light radius of 34 pc and a systemic velocity of  ∼−40 km s⁻¹  . Our data also provide evidence for a stream around Segue 2 at a similar heliocentric velocity, and the SEGUE data show that it is also present in neighbouring fields. We resolve the velocity dispersion of Segue 2 as 3.4 km s⁻¹ and the possible stream as  ∼7 km s⁻¹  . This object shows points of comparison with other recent discoveries, Segue 1, Boo II and Coma. We speculate that all four objects may be representatives of a population of satellites of satellites – survivors of accretion events that destroyed their larger but less dense parents. They are likely to have formed at redshifts   z > 10  and are good candidates for fossils of the reionization epoch.     

Modeling of lightcurves of binary asteroids

We present a numerical method for inverting long-period components of lightcurves of asynchronous binary asteroids. Data of five near-Earth binary asteroids, (175706) 1996 FG₃, (65803) Didymos, (66391) 1999 KW₄, (185851) 2000 DP₁₀₇ and (66063) 1998 RO₁, for two of them from more than one apparition, were inverted. Their mutual orbits' poles and Keplerian elements, size ratios, and ellipsoidal shape axial ratios were estimated via this inversion. The pole solutions and size ratios for 1999 KW₄ and 2000 DP₁₀₇ are in a good agreement with independent estimates from radar measurements. We show that uncertainties of estimates of bulk densities of binary systems can be large, especially when observed on short arcs.     

Investigation of Times of Minima of Selected Early-Type Eclipsing Binaries

New precise times of minimum light for several early-type eclipsing binaries were obtained at three observatories. The changes of period of the following measured binaries are discussed: V1182 Aql, LY Aur, SZ Cam, FZ CMa, QZ Car, LZ Cen, V606 Cen, AH Cep and TU~Mus.