共查询到20条相似文献，搜索用时 31 毫秒
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We report optical time‐resolved photometry of the CRTS transient CSS091109:035759+102943. Pronounced orbital variability with a 114 min period, large X‐ray variability and the IR to X‐ray spectral energy distribution suggest a classification as a magnetic cataclysmic binary, a likely AM Herculis star or polar (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Miquel Grau Guillermo González-Casado 《Celestial Mechanics and Dynamical Astronomy》1998,72(3):169-186
A comparative study of the evolution of the Sun–Jupiter–Asteroid system near the 4:1 and 7:2 resonances is performed by means
of two techniques that proceed differently from the Hamiltonian corresponding to the planar restricted elliptic three-body
problem. One technique is based on the classical Schubart averaging while the other is based on a mapping method in which
the perturbing part of the Hamiltonian is expanded and the resulting terms are ordered according to a weight function that
depends on the powers of eccentricities and the coefficients of the terms. For the mapping method the effect of Saturn on
the asteroidal evolution is introduced and the degree of chaos is estimated by means of the Lyapunov time. Both methods are
shown to lead to similar results and can be considered a suitable tool for describing the evolution of asteroids in the Kirkwood
gap and the group corresponding to the 4:1 and 7:2 Jovian resonances, respectively.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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《Planetary and Space Science》1999,47(8-9):1101-1109
The ten-degree tilt of the Jovian magnetic dipole causes the magnetic equator to move back and forth across Jupiters rotational equator and the Galileo orbit that lies therein. Beyond about 24 Jovian radii, the equatorial current sheet thins and the magnetic structure changes from quasi-dipolar into magnetodisk-like with two regions of nearly radial but antiparallel magnetic field separated by a strong current layer. The magnetic field at the center of the current sheet is very weak in this region. Herein we examine the current sheet at radial distances from 24–55 Jovian radii. We find that the magnetic structure very much resembles the structure seen at planetary magnetopause and tail current sheet crossings. The magnetic field variation is mainly linear with little rotation of the field direction. At times there is almost no small-scale structure present and the normal component of the magnetic field is almost constant through the current sheet. At other times there are strong small-scale structures present in both the southward and northward directions. This small-scale structure appears to grow with radial distance and may provide the seeds for the explosive reconnection observed at even greater radial distances on the nightside. Beyond about 40 Jovian radii, the thin current sheet also appears to be almost constantly in oscillatory motion with periods of about 10 min. The amplitude of these oscillations also appears to grow with radial distance. The source of these fluctuations may be dynamical events in the more distant magnetodisk. 相似文献
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V. I. Burnashev B. A. Burnasheva 《Bulletin of the Crimean Astrophysical Observatory》2008,104(1):102-108
Based on the SIMBAD database, we collected necessary information on the comparison stars used by E. Schenfeld in observations of variable stars in the 19th century. 相似文献
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小型激光天文动力学空间计划概念 总被引：1，自引：0，他引：1
倪维斗 朱进 武向平 褚桂柏 杨彬 高健 关敏 汤健仁 周翊 张中豪 黄天衣 曲钦岳 易照华 李广宇 陶金河 吴岸明 罗俊 叶贤基 周泽兵 熊耀恒 毕少兰 须重明 吴雪君 唐孟希 包芸 李芳昱 黄珹 杨福民 叶叔华 张书练 张元仲 聂玉昕 陈光 Joergen Christensen-Dalsgaard Hansjoerg Dittus Yasunori Fujii Claus Laemmerzahl Jean Francois Mangin Achim Peters Albrecht Ruediger Etienne Samain Stephan Schiller 《天文研究与技术》2002,(3):123-136
小型激光天文动力学空间计划是 :使用在太阳轨道上无拖曳航天器和地面站以激光干涉和脉冲测距的方法 ,精确地探讨天文动力学 ,检测相对论与时空基本定律 ,改进探测引力波的灵敏度以及更准确地测定太阳、行星和小行星的参数。 1 969年开始的月球激光 (反射 )测距 ,对地球物理、参考坐标的选定、相对论的检验均有重要的贡献。 3 0年来 ,激光技术的长足进步 ,使现在正是适合于开始进行研究空间有源 (主动 )测距和光波空间通讯的时候。激光天文动力学的兴起是必然的趋势 ,其精确度将比现在提高 3到 6个数量级 ,将是天文动力学革命性的发展。小型激光天文动力学空间计划可以起到带头作用。它的关键技术有三 ,即 :弱光锁相、极精确无拖曳航天和高衰减日冕仪。弱光锁相已有长足的进步。对高衰减日冕仪的研究 ,也有了初步的方案。LISA空间计划将于 2 0 0 6年 8月发射SMART -2 ,研究测试极精确无拖曳航天。小型激光天文动力学空间计划的关键技术已日趋成熟。在第一届国际激光天文动力学研讨会 ( 2 0 0 1 ,9.1 3 -2 3 )中介绍了各相关学科背景及前沿研究 ,讨论了激光天文动力学空间计划科学目标及相关技术 ,并召开了两次小型激光天文动力学空间计划预研究筹备会 ,建立了和欧洲的合作关系。会后着手进行此项对基础 相似文献
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J. B. Zirker 《Solar physics》1989,120(2):253-259
Non-redundant arrays offer a promising technique for producing diffraction-limited solar images. Pairs of two-dimensional non-redundant arrays yield sufficient information to recover the phases of all the spatial frequencies to which they respond. The algorithms to select and test such pairs are given and applied to a particular example.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. 相似文献
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The European Near Earth Asteroid Research (EURONEAR) is a project which envisions to build a coordinated network which will follow-up and recover potentially hazardous asteroids (PHAs) and near earth asteroids (NEAs). We aim to include in EURONEAR two automated 1 m telescopes located in Chile and Europe, in addition to other non-permanent facilities. Astrometry will be the main aim of the project in order to secure and follow-up newly discovered NEAs, also to recover PHAs at their second or following oppositions, while photometry of bright PHAs will bring information on their physical properties. In this paper, first we review briefly the existent and past NEAs programs. Next, we include the results obtained in 2006 from three observing runs at Pic du Midi using the 1 m telescope, Haute-Provence employing the 1.2 m telescope, and Bucharest using a small 23 cm telescope. These add a total of 153 positions for 16 PHAs and NEAs, which were accepted by Minor Planet Center. Recently, a 1 m telescope was allocated by ESO in La Silla to be automated and used as the Southern dedicated facility by EURONEAR. 相似文献
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