依巴谷天体测量卫星的阶段成果

本文综合介绍依巴谷天体测量卫星自１９８９年１１月开始观测以来，由头两年获得的观测资料取得的空间天体测量的阶段性成果，以及空间天体测量结果与地面观测结果相互之间的比较，成功地用于解算天体测量参数的星数已达１１２４４颗，由依巴谷天体测量卫星的头两年观测资料进行归算处理，得到恒星位置，视差和年自行的预期精度分别为３、４和２ｍａｓ。由此从整体上合面地检验了依巴谷科学计划，包括观测纲要，输入星表，卫星本身及     

CCD在空间天体测量上的应用

本文分析了依巴谷空间天体测量卫星主探测器析像管和恒星测绘仪的工作缺点;介绍了用CCD作为HIPPARCOS主探测器的优越性,预期的观测结果,以及误差分析比较。     

空间天体测量新进展

主要评述依巴谷卫星的成功与不足，评价近年来一系列新的空间天体测量技术，着重评 默计划和波因次计划的新进展。     

近三年来国际上天体测量研究的进展

本文简述近三年来国际上天体测量的研究进展 ,特别是依巴谷星表向暗星扩充、2 0世纪初照相观测改进自行的精度和巡天观测资料对特殊天体物理现象的检测等方面的研究动态。最后介绍了空间天体测量卫星DIVA、GAIA、SIM和FAME计划的进展。     

空间时代地面光学天体测量的意义

从基本天体测量的主要任务出发，介绍了绝对测定和相对测量之间的区别和不同用途，并针对河外射电源参考架和依巴谷参考架的高精度的不足之处，说明了地面光学天体测量的长期性和灵活性等优势正是克服这些不足之处所必须的，但这不应是传统的已有精度下的地面光学天体测量，而应是与空间测量精度可比的要求下的地面测量，两者配合起来，将能促进本学科和相关学科的发展。     

依巴谷卫星和哈勃空间望远镜的天体测量观测结果

综述了以下几个方面的工作：（１）依巴谷卫星３０个月观测资料的初步处理结果；（２）空间望远镜精密导星传感器的性能测试；（３）依巴谷卫星和空间望远镜近期在观测和仪器改进上的进展；（４）我们开展空间天体测量工作的概况。     

未来10年天体测量的发展

首先回顾了依巴谷卫星的观测结果在天文学上的意义,同时指出其不足之处,极限星等仅为 １２ｍａｇ,自行精度不够高等,介绍了正在进行的各种地面上的暗星扩充计划,如ＴＡＣ、ＳＤＳＳ、ＵＣＡＣ－Ｓ,ＰＯＳＳ等,并对它们的预期计划和目前进展情况作了详细描述。叙述了未来１０年可能实施的几个空间天体测量计划,如欧洲空间的ＧＡＩＡ,美国喷气推进实室的ＳＩＭ,德国的ＤＩＶＡ,美国海军天文台的ＦＡＭＥ和俄罗普尔科沃天文     

世纪之交空间天体测量新纪元

本文主要论述二十世纪末二十一世纪初空间天体测量新计划、新技术、以及高精度天体测量在天体物理中的应用。     

依巴谷星表和第谷星表的特征和意义

主要论述依巴谷星表和第谷星表的观测特征和天体测量特征,依巴谷卫星在短期内同时测定大量高精度的恒星位置,自行和视差等五个天体测量参数以及星等和色指数,依巴谷星表和第谷星表为建立高精度的光学参考系,为研究恒星的起源,演化,分布,质量,大小和光度等,为研究双星和聚星的分布和运动,为研究星系运动和星系动力学提供了大量的高精度资料,具有重要的科学意义。     

第二个天体测量卫星(Gaia)项目的进展

简述了第二个天体测量卫星Gaia(将于2013年3月发射)项目的科学意义,并给出了该项目的组织工作和最近的进展.描述了Gala观测资料处理的基本原理,以及与依巴谷观测资料处理的不同点.介绍了Gaia参考架构建的考虑,以及为了构建微角秒量级的参考架,应在自行中加入系统差改正,如长期光行差、引力波效应、宇宙膨胀各向异性的影响,弱的微引力透镜和微引力透镜噪声效应等.介绍了Gaia光学参考架与射电参考架ICRFL2之间建立联系过程中,选择河外射电源的准则,其中包括源的核漂移和光学长期变化监测等.最后,提出了我国现有设备参与支持Gaia的地基观测,以及正在研制的65 m射电天线在射电天体测量方面可以开展的若干课题.     

近10年我国天体测量的发展

简述天体测量学研究的内各以及与各相关学科之间的关系；描述近10年来国际天体测量研究的进展和前沿课题；叙述我国天体测量研究的历史背景和研究基础，以及近10年来在国家自然科学基金委员会和其他科学组织支持下取得的成果，并对今后10～20年我国天体测量的发展提出初步看法。     

Space-borne global astrometric surveys: the hunt for extrasolar planets

The proposed global astrometry mission GAIA , recently recommended within the context of ESA's Horizon 2000 Plus long-term scientific programme, appears capable of surveying the solar neighbourhood within ∼200 pc for the astrometric signatures of planets around stars down to the magnitude limit of V =17 mag, which includes late M dwarfs at 100 pc.
Realistic end-to-end simulations of the GAIA global astrometric measurements have yielded the first quantitative estimates of the sensitivity to planetary perturbations and of the ability to measure their orbital parameters. Single Jupiter-mass planets around normal solar-type stars appear detectable out to 150 pc ( V ≤12 mag) with probabilities ≥50 per cent for orbital periods between ∼2.5 and ∼8 yr, and their orbital parameters are measurable with better than 30 per cent accuracy to about 100 pc. Jupiter-like objects (same mass and period as our giant planet) are found with similar probabilities out to 100 pc.
These first experiments indicate that the GAIA results would constitute an important addition to those that will come from the other ongoing and planned planet-search programmes. These data combined would provide a formidable testing ground on which to confront theories of planetary formation and evolution.     

Astrometry from space: GAIA and planet detection

The proposed baseline GAIA mission will be able to detect the astrometric signature of Jupiter-size planets around of the order of a million stars, using either global or narrow-angle astrometry. If the mission can realize the higher astrometric accuracy that photon statistics allows for bright stars, lower-mass planets (from Earth size to ten times larger) can be found around ten to a few hundred stars.     

Impact of the atmospheric refraction on the precise astrometry with adaptive optics in infrared

We study the impact of the atmospheric differential chromatic refraction on the measurements and precision of relative astrometry. Specifically, we address the problem of measuring the separations of close pairs of binary stars with adaptive optics in the J and K bands.We investigate the influence of weather conditions, zenithal distance, star’s spectral type and observing wavelength on the astrometric precision and determine the accuracy of these parameters that is necessary to detect exoplanets with existing and planned large ground based telescopes with adaptive optics facilities. The analytical formulae for simple monochromatic refraction and a full approach, as well as moderately simplified procedure, are used to compute refraction corrections under a variety of observing conditions.It is shown that the atmospheric refraction must be taken into account in astrometric studies but the full procedure is not necessary in many cases. Requirements for achieving a certain astrometric precision are specified.     

Astrometric detection of Earth-like planets with OSI

The Orbiting Stellar Interferometer (OSI) is a space-based astrometric interferometer designed primarily for wide-angle astrometry. OSI is potentially capable of achieving astrometric accuracies of 1as in narrow angle (1°) astrometry. This paper discusses the implications for astrometric planet detection, specifically the detection of Earth-like planets around nearby stars. OSI has the potential to detect a limited number of planetary systems with Earths, if a number of technical problems are solved.     

全天相机在多设备巡天中的应用

天文观测站夜天空星像星等信息和天区分布信息可用于指导多设备巡天观测.建立全天相机监测系统(Monitoring all-sky system)对本地天区夜天空实时监测,获取的监测图像需要有效的方法进行处理以提取全天图像星像信息.由于全天图像视场大和高阶扭曲的影响,采用天顶等距投影与多项式函数组合的方法计算图像的底片常数.天文定位的均方根残差约为0.15个像素.通过对图像中亮星部分测光得到的星等差,改正大气消光误差.最后使用HEALPix (Hierarchical Equal Area isoLatitude Pixelation)方法实现天区划分和每个天区可观测极限星等值的存储.     

The proper-motion signal of unresolved binaries in the Hipparcos catalogue

We present an investigation of the differences between quasi-instantaneous stellar proper motions from the Hipparcos catalogue and long-term proper motions determined by combining Hipparcos and the Astrographic Catalogue. Our study is based on a sample of about 12000 stars of visual magnitude from 7 to 10 in two declination zones on the northern and equatorial sky. The distribution of the proper-motion differences shows an excess of large deviations. This is caused by the influence of orbital motion of unresolved binary systems. The proper-motion deviations provide statistical evidence for 360 astrometric binaries in the investigated zones, corresponding to about 2400 such binaries in the entire Hipparcos catalogue, in addition to those already known. In order to check whether the observed deviations are compatible with standard assumptions on the basic parameters of binary stars, we model the impact of orbital motion on the observed proper motions in a Monte Carlo simulation. We show that the simulation yields an acceptable approximation of the observations, if a binary frequency between 70% and 100% is assumed, i.e.if most of the stars in the sample are assumed to have a companion. Thus Hipparcos astrometric binaries confirm that the frequency of non-single stars among field stars is very high. We also investigate the influence of the mass function for the secondary component on the result of the simulation. A constant mass function and mass functions with moderate increase towards low masses lead to results, which are compatible with the observed proper-motion effects. A high preponderance of very-low-mass or substellar companions as produced, for example, by a M^—1 power law is not in agreement with the frequency of proper-motion deviations in our sample of stars.     

The Representation of OTA Images’ Astrometric Results with WCS-SIP Coefficientstwo

Cross-matching the sources in the observed image with the star catalogs or earlier records is a necessary procedure for detecting the position or brightness variation of a specific source in the Optical Telescopes Array (OTA) survey. Therefore, knowing the celestial positions of these objects on the observed image is prerequisite. A method based on matrix manipulation is applied to converting the existing plate constants of OTA images into the World Coordinate System (WCS) and Simple Imaging Polynomial (SIP) coefficients, and recording such mapping relations on the FITS (Flexible Image Transport System) files of OTA for the convenience of use. The improvement on the astrometry of OTA resulted by this method, as well as the discussion about some problems of the OTA astrometry are also presented.     

Astrophysical supplements to the ASCC‐2.5. I. Radial velocity data

We present a catalogue of radial velocities of Galactic stars with high precision astrometric data CRVAD which is the result of the cross‐identification of star lists from the General Catalog of Average Radial Velocities (GCRV) and from the homogeneous All‐sky Compiled Catalogue of 2.5Million Stars (ASCC‐2.5). The CRVAD includes accurate J2000 equatorial coordinates, proper motions and trigonometric parallaxes in the Hipparcos system, Johnson's BV photometric data, spectral types, multiplicity and variability flags from the ASCC‐2.5, and radial velocities, stellar magnitudes and spectral types from the GCRV for 34553 ASCC‐2.5 stars. The CRVAD was used for the construction of a sample of standard stars with accurate astrometric, photometric and radial velocity data for the RAVE project. A second application of the CRVAD , the radial velocity determination for 292 open clusters (including 97 with previously unknown radial velocities), using their newly defined members from proper motions and photometry in the ASCC‐2.5, is briefly described. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)