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     

昴星团天体测量标准区域441颗星的高精度位置和自行

本文利用由ＰＰＭ和ＡＣＲＳ星表以及Ｅｉｃｈｈｏｒｎ等、Ｊｏｎｅｓ和Ｈｅｒｔｚｓｐｒｕｎｇ的星表综合而成的初始参考星表，对佘山４０厘米折射望远镜拍摄的历元间隔８６年１１张底片上３３次露光按中心重叠法进行归算，得出了昂星团天体测量标准区域４４１颗星的高精度位置和自行，这些位置的标准误差均小于±０．″０５，接近百分之九十恒星的自行标准误差小于±０〃．００１／年．     

用照相底片精确测定依巴谷星的自行

利用上海天文台佘山40cm折射望远镜拍摄的历元间隔约为27年的6张底片,共计有14次露光观测,以PPM星表作为初始参考星表,按中心重叠法进行归算,得到了南天区域内21颗恒星的高精度位置和自行,其中有6颗是依巴谷星,它们的赤经和赤纬精度的平均值分别为1.8ms和22mas ,赤经自行和赤纬自行精度的平均值分别灰0.068ms/a和0.97mas/a。     

31颗射电星的位置和自行

在１９８５年至１９８８年间，用佘山４０ｃｍ天体照相仪进行了射电星观测，得出３１颗射电星在ＦＫ５系统中的位置和自行，并将所得的自行值和ＰＰＭ及ＣＡＭＣ星表中的相应结果作了比较。     

31颗射电星的位置和自行

在１９８５年至１９８８年间，用佘山４０ｃｍ天体照相仪进行了射电星观测，得出了３１颗射电星在ＦＫ５系统中的位置和自行。并将所得的自行值和ＰＰＭ及ＣＡＭＣ星表中的相应结果作了比较     

离太阳系最近的褐矮星

最近,一个欧洲天文学家小组发现了一颗离太阳系最近、天空中最亮的T光谱型褐矮星。这颗褐矮星是印第安座ε的一颗遥远伴星。印第安座ε位于11.8光年的南天,是肉眼可见的近距恒星,也是天文学家和科幻作家耳熟能详的恒星,它的新伴星命名为印第安座εB,是近15年发现的最近的,并且是自20世纪30年代以来有最大自行的类星天体。它大     

深空照相天图集

略要地回顾了应用广角天体照相似的照相天图发展历史。简要地介绍了十二种著名的巡天星图。文章评述了施密特光学系统发明以来的四种深空天图,它们是帕洛玛天图、ESO/SRC南天天图、帕洛玛银道带红外天图和南天红外天图。最后,介绍了应用帕洛玛天图所取得的成就,还展望了新的天图计划。     

迷人的天炉座

天炉座的拉丁语名称为Formax,意为“熔炉”,属南天星座之一,因为它的纬度极低,所以北半球大部分地区的人们无法看到它。天炉座东边被波江座所包围,西接玉夫座,位于鲸鱼座与凤凰座之间。每年11月2日子夜,天炉座的中心经过上中天。在北纬50度以南的广大地区可以看见完整的天炉座,在北纬64度以北的地区则完全看不到它。公元1751～1753年间,法国天文学家拉卡伊和拉朗德同时在柏林和好望角测量月亮的天顶距,首次用三角视差法(2006年第12期《天文爱好者》中何香涛教授的“追逐类星体”一文对此方法有详细介绍——编者)测出月亮与地球的距离约为地球半径的60倍。拉卡伊在好望角观测了暗至7等的一万多颗星,还命名了许多南天星座,其中有14个沿用至今。     

欧南台观测钱德拉深空天区

三个欧洲天文学家小组获得了南天一个区域的真彩色,最深的大视场图像。这一成果补充了钱德拉X射线天文台在天炉座方向的南深空天区观测(CDF-S)。CDF-S是1999年曝光100万秒获得的,如此长的曝光足能探测到可以观测到的最暗的X射线源。 新图像是由智利拉西亚天文台的2.2米MPG/ESO望远镜上的大视场成像器(WFI)拍摄的。WFI是用     

用照相底片改进依巴谷星的自行

本文用佘山４０厘米折射望远镜拍摄的历元间隔约为３０年的９张底片上共１７次露光观测，以ＰＰＭ星表作为初始参考星表，用中心重迭法进行叠代归算，得到了射电源０３１６十４１３附近的２８颗星的高精度位置和自行，其中６颗为依巴谷星，这些依巴谷星的赤经自行和赤纬自行内部误差的平均值分别为■年和■年．     

Discovery of a companion at the brown dwarf limit to the solar‐type star Gliese 29

Gliese 29 is a 7 to 8 Gyr old, southern Population I turnoff star with a large proper motion of 1″/yr. Using recent direct imaging observations with the 0.8 m Infrared Imaging System (IRIS) of the Universitätssternwarte Bochum near Cerro Armazones in Chile, we demonstrate that the faint source 2MASS J00402651–5927168 at a projected angular separation ρ = 6.″35 is a common‐proper‐motion companion to Gl 29. Provided this source is not part of a further subsystem, the IRIS J ‐ and K_s‐band photometry either implies a spectral type of about L2, based on its absolute magnitude, or an approximate mass M_B ≃ 0.077 M_⊙, suggesting that it may even be a brown dwarf. Assuming a face‐on circular orbit this faint companion orbits Gl 29 in 1880 years. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Kiev photographic catalogues of stellar proper motions: Compilation and application

The works of the Goloseevo Observatory (Kiev, U.S.S.R.) on the compilation of catalogues of absolute proper motions measured with respect to faint galaxies are discussed. Using these catalogues, some astrometric and stellar characteristics have been obtained. Particular attention is paid to the problem of improving the accuracy of stellar position and proper motion determinations. The optimum procedure for compiling the consolidated catalogue intended for the improvement of fundamental reference frame, kinematic characteristics of stars as well as for the solution of applied problems is developed.     

New nearby stars among bright APM high proper motion stars

As part of a new southern sky survey for faint high proper motion stars based on Automatic Plate Measuring (APM) measurements of UK Schmidt Telescope plates, we have found a large number of previously unknown brighter objects. Spectroscopic follow-up observations with the European Southern Observatory New Technology Telescope of 15 of these new, relatively bright     high proper motion stars     show one-third of them to be nearby     . Among the nearby stars is an M6 dwarf with strong emission lines at a spectroscopic distance of about 11 pc and an M4 dwarf at about 13 pc. Coupled with earlier South African Astronomical Observatory spectroscopic observations of three similar bright high proper motion stars, the success rate of finding nearby stars     is about 45 per cent. All newly discovered nearby stars have disc kinematics confirmed by radial velocity measurements from our spectra. In addition there are several high-velocity stars with halo kinematics in the sample, mainly subdwarfs, at about 60 to 110 pc distance. These high-velocity stars are interesting targets for further study of the Galactic escape velocity. One of the detected nearby high proper motion stars was formerly thought to be an M giant in the Small Magellanic Cloud. The spectrum of one M3 star shows a strong blue continuum, which is likely to signify the presence of a hot companion. Spectroscopic follow-up observations of high proper motion stars are shown to be an effective tool in the search for the missing stars in the Solar neighbourhood. Candidates for more extensive trigonometric parallax determination can be selected on the basis of the spectroscopic distance estimates.     

Near-infrared imaging survey of faint companions around young dwarfs in the Pleiades cluster

We conducted a near-infrared imaging survey of 11 young dwarfs in the Pleiades cluster using the Subaru Telescope and the near-infrared coronagraph imager. We found ten faint point sources,with magnitudes as faint as 20 mag in the K-band,with around seven dwarfs.Comparison with the Spitzer archive images revealed that a pair of the faint sources around V 1171 Tau is very red in infrared wavelengths,which indicates very low-mass young stellar objects.However,the results of our follow-up proper motion measure...     

Observing programs for the Pulkovo Horizontal meridian circle

Observing programs are discussed for the Pulkovo automatic horizontal meridian circle. The instrument is highly efficient and yields precise and accurate positions. We prepare an observing program of faint FK5 stars with the aim of improving on the system of this catalogue and also prepare a program of observations of IRS reference catalogue stars.     

A search for nearby counterparts to the moving objects in the Hubble Deep Field

Ibata et al. have recently discovered very faint, moving objects in the Hubble Deep Field (HDF). The number, apparent magnitudes and proper motions of these objects are consistent with old white dwarfs making up part of the Galactic dark halo. We review a number of ground-based proper motion surveys in which nearby dark-halo white dwarfs might be present, if they have the colours and absolute magnitudes proposed. No such objects have been found, whereas we argue here that several times more would be expected than in the HDF. We conclude that it is unlikely that hydrogen-atmosphere white dwarfs make up a significant fraction of the Galactic dark matter. No limits can be placed as yet on helium-atmosphere dwarfs from optical searches.     

The SuperCOSMOS Sky Survey – III. Astrometry

In this, the third in a series of three papers concerning the SuperCOSMOS Sky Survey, we describe the astrometric properties of the data base. We describe the algorithms employed in the derivation of the astrometric parameters of the data, and demonstrate their accuracies by comparison with external data sets using the first release of data, the South Galactic Cap survey. We show that the celestial coordinates, which are tied to the International Celestial Reference Frame via the Tycho–2 reference catalogue, are accurate to better than ±0.2 arcsec at J , R ∼19,18 , rising to ±0.3 arcsec at J , R ∼22,21 , with positional-dependent systematic effects from bright to faint magnitudes at the ∼0.1-arcsec level. The proper motion measurements are shown to be accurate to typically ±10 mas yr⁻¹ at J , R ∼19,18 , rising to ±50 mas yr⁻¹ at J , R ∼22,21 , and are tied to zero using the extragalactic reference frame. We show that the zero-point errors in the proper motions are ≤1 mas yr⁻¹ for R >17 , and are no larger than ∼10 mas yr⁻¹ for R <17 mas yr⁻¹ .     

低纬子午环配备科学CCD后的课题目标

针对低纬子午环配备科学ＣＣＤ后的观测能力，叙述了该仪器观测的课题目标：为建立准惯性天球参考架提供充分的观测数据，为建立动力学参考架和太阳系动力学研究提供天然卫星和小行星的高精度数据，为银河系结构和运动学研究提供必要的数据，为某些天体物理课题研究提供有用的数据，为地球动力学和天文地震研究提供基本的测量数据。将来编制观测纲要时，会兼顾到这些方面的需要，合理安排，以求充分发挥该仪器的作用。     

自行与银河系研究的前沿

简述了精确测定相对自行的方法,特别介绍了在用2～3个历元的底片和CCD观测结果推导恒星自行的过程中如何消除光学视场畸变、星等差和色差的具体办法;并介绍了用星系把相对自行推算绝对自行的方法。还介绍了用自行资料研究银河系结构和演化的一些前沿课题,其中包括星团研究、与银河系兼并的矮星系的发现、暗物质的检测、外星行星的探测和银河系中心黑洞的质量估算等。最后评价了自行在研究银河系中的重要性,论述了我国研制4m光学/近红外望远镜的重要意义。     

The UKIDSS–2MASS proper motion survey – I. Ultracool dwarfs from UKIDSS DR4

The UK Infrared Telescope Infrared Deep Sky Survey (UKIDSS) is the first of a new generation of infrared surveys. Here, we combine the data from two UKIDSS components, the Large Area Survey (LAS) and the Galactic Cluster Survey (GCS), with Two-Micron All-Sky Survey (2MASS) data to produce an infrared proper motion survey for low-mass stars and brown dwarfs. In total, we detect 267 low-mass stars and brown dwarfs with significant proper motions. We recover all 10 known single L dwarfs and the one known T dwarf above the 2MASS detection limit in our LAS survey area and identify eight additional new candidate L dwarfs. We also find one new candidate L dwarf in our GCS sample. Our sample also contains objects from 11 potential common proper motion binaries. Finally, we test our proper motions and find that while the LAS objects have proper motions consistent with absolute proper motions, the GCS stars may have proper motions which are significantly underestimated. This is possibly due to the bulk motion of some of the local astrometric reference stars used in the proper motion determination.