共查询到18条相似文献，搜索用时 93 毫秒
1.
使用全球ＶＬＢＩ网在１．３ ｃｍ波段对三颗类星体０４２０－０１４、０７４８＋１２６和２２５１＋１５８（３Ｃ ４５４．３）进行了观测,获得了这三个类星体的亚毫角秒分辨率的混杂图,给出了类星体核区内的亮度分布．通过用高斯模型对观测数据进行拟合,得到了组成它们的各个子源的参数．类星体２２５１＋１５８呈现出核－喷流结构,核区沿着ＰＡ～－１３０°方向拉长,喷流呈弯曲状．１９９２．９历元的观测展现了２２５１＋１５８处于一次大爆发,并伴随一系列相继出现的小爆发的情景．最强子源的积分流量密度为 ４．１１Ｊｙ（占探测到的总流量的 ６７％）,主要集中在０．１６ × ０．０１ ｍａｓ的区域内,可能由于多普勒增亮效应造成高达２．６×１０１２的亮温度． 相似文献
2.
１９９７年３月９日日全食８．６ｍｍ波段射电观测资料的分析表明：８．６ｍｍ波段射电太阳的半径为１．０１２Ｒ,总流量为２５４０ｓｆｕ（１ｓｆｕ＝１０－２２Ｗ／ｍ２Ｈｚ）,日面平均亮温度为９６３２Ｋ,径向亮温度分布,在日面光学边缘内侧０．９３６－０．９９２Ｒ处,存在临边增亮,平均增亮幅度相对于日面中心为９．７％． 相似文献
3.
俞志尧 《中国天文和天体物理学报》1999,(1)
分析ＣｅｐｈｅｕｓＥ中Ｃ１８Ｏ（Ｊ＝１－０）的速度位置图,发现相对于峰速度的红移速度成分主要分布在中心位置附近的核区,而相对于峰速度的蓝移速度成分除了分布在中心位置附近的核区外,还可以在向东和向西北方向的外流中找到。这说明强度分布图中的分子外流的不准直分布是由相对于峰速度的蓝移速度成分的不准直分布所引起的。 相似文献
4.
在漠河１９９７年３月９日日全食期间,使用３°测量视场的光电光度计,测量了日冕总光通。仪器的光谱响应符合Ｖ（λ）函数,测量结果：太阳黑子极小期日冕的总光通Φｃ与太阳总光通Φｓ之间的关系为Φｃ＝０．６９×１０－６Φｓ。 相似文献
5.
给出１９９７年３月９日日全食时所作的日冕偏振ＣＣＤ观测资料的处理结果,包括太阳赤道东西和两极等十二个方向的中冕（１．６￣３．２Ｒ⊙）绝对亮度分布和偏振度分布。 相似文献
6.
用非均匀模型,对１９８１年４月２７日０８００１Ｔ大耀斑进行了分析。从硬Ｘ射线和微波爆发的观测频谱出发,在假定周围离子密度ｎｉ＝３×１０１０／ｃｍ３的情况下,计算得到两者的总电子数ＮＸ和ＮＲ是近似相等的。这表明,至少对这个耀斑,两者的非热电子可能有同样的分布。此外,文中也分析了ＮＲ提高了１０３－１０４倍的原因可能在于磁场的非均匀性和源中的磁场值较小。 相似文献
7.
利用紫金山天文台青海站的 １３．７ ｍ毫米波望远镜,对 Ｏｒｉｏｎ Ａ分子云中的 ＯＭＣ－３区域,进行了较高分辨率的１３ＣＯ（Ｊ＝１－０）和Ｃ１８Ｏ（Ｊ＝１－０）分子辐射的成图观测．给出了该分子云中１３ＣＯ和 Ｃ１８Ｏ云核分布的整体结构和平均物理参数．观测发现,该分子云的１３ＣＯ和 Ｃ１８Ｏ的云核中心分别与最年轻的天体－Ｃｌａｓｓ ０类源 ＭＭＳＩ, ＭＭＳ４,ＭＭＳ６和ＭＭＳ７,ＭＭＳ８;ＭＭＳ９成协．此外,通过分析ＯＭＣ－３整个区域的速度场结构,发现沿 Ｃ１８Ｏ和１３ＣＯ云核方向从南到北有一个～ １．７ｋｍ／ｓ的速度场梯度,而分子云的红、蓝移团块则分别趋于云的北部和南部．并对ＯＭＣ－３区的恒星形成特征进行了讨论． 相似文献
8.
１９９１年３月，我们利用上海２５ｍ射电望远镜和欧洲ＶＬＢＩ网联合对几个河外射电源进行了第二历元的３２７ＭＨｚＶＬＢＩ观测．数据的相关处理先后在上海天文台三台站ＭＫ２相关处理机和美国的Ｃａｌｔｅｃｈ／ＪＰＬ相关处理机进行，以便于比较相关结果。本文给出３Ｃ８４、３Ｃ３４５和３Ｃ３８０的混合图。与第一历元的观测比较，３Ｃ３４５和３Ｃ３８０的流量密度没有明显的变化，但３Ｃ３４５的结构变化明显。３Ｃ８４和３Ｃ３４５有喷流的迹象．３Ｃ４５４．３的总流量在不到两年的时间内增加了２５％，如果这个变化是内禀的话，那么可能意味着一次新的流量爆发。 相似文献
9.
简要综述了近年来对于星际ＣＨ３ＯＨ脉泽的观测和研究成果，对ＣＨ３ＯＨ脉泽的性质从分类，生成区域及分布，辐射特性，运动状况等方面做了介绍，并阐明了理论上对其时变特性，激发机制及河外脉泽的探讨，最后对两种类型的ＣＨ３ＯＨ脉泽作了对比和讨论。 相似文献
10.
本文发表了强活动色球双星ＨＲ１０９９（＝Ｖ７１１Ｔａｕ）在１９８９年１２月特大能量白光耀发前后的近红外分光光度观测结果，给出该星从２．３－４．１μｍ首次ＣＶＦ低色散光谱，以及耀发前后的变化；计算了同期观测到的子星表面黑子的影响，给出双星黑体近似辐射能谱，并与多波段测光以及ＩＲＡＳ观测作了对比，揭示了该双星有很强的星周物质的２．３μｍ发射带和３．１μｍ波段吸收带特征，本文对可能的星周物质成分和分布亦作了初步讨论。 相似文献
11.
Jing-xiu Wang 《Chinese Astronomy and Astrophysics》1986,10(4):291-297
An analysis of magneto-acoustic-gravity waves in the case of an isothermal atmosphere permeated by a uniform magnetic field is presented. The general solution is expressed in terms of generalized hypergeometric functions. It can be used in numerical simulation of oscillations in a magnetic atmosphere.
It is shown that the elliptically polarized magneto-acoustic-gravity waves consist of a pair of surface waves and a pair of body waves above the cut-off frequency. The body waves along the magnetic field are similar to acoustic waves in an atmosphere and their cut-off frequency is unaffected by magnetic field. The transverse oscillation decreases with height. For the usual boundary condition, the longitudinal oscillation decreases with height; however, in some cases, it may contain terms that increase with height. The solution is singular on a family of ellipses in the frequency - horizontal wave number plane. Near these ellipses, the wave components grow indefinitely. 相似文献
12.
Quan-Ming Lu Shui Wang School of Earth Space Sciences University of Science Technology of China Hefei 《中国天文和天体物理学报》2005,5(2):184-192
We carried out one-dimensional hybrid simulations of resonant scattering of protons and He^2 ions by ion cyclotron waves in an initially homogeneous, collisionless and magnetized plasma. The initial ion cyclotron waves have a power spectrum and propagate both outward and inward. Due to the resonant interaction with the protons and He^2 ions, the wave power will be depleted in the resonance region. Both the protons and He^2 ions can be resonantly heated in the direction perpendicular to the ambient magnetic field and leading to anisotropic velocity distributions, with the anisotropy higher for the He^2 ions than for the protons. At the same time, the anisotropies of the protons and He^2 ions are inversely correlated with the plasma β‖p=8πnpkBT‖p/B0^2, consistent with the prediction of the quasilinear theory (QLT). 相似文献
13.
Yan-Ben Han Qi-Yuan Qiao National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2003,3(6):569-575
We address the relation between an ancient total eclipse, which occurred on A.D.1542 August 11 and the variation of Earth‘‘s rotation. The total eclipse was recorded in some ancient Chinese books, especially in local chronicles. Some of the documents include useful information for determining the location of the totality zone. The parameters of the eclipse are calculated by using the DE406 Ephemeris.A high-precision value of AT which expresses the variation of the Earth‘‘s rotation,of about 300 ～ 380 s, is obtained. 相似文献
14.
Xiao-Cong Li Lian-Sheng KangNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2005,5(1):110-116
A statistical analysis is made on the correlation between solar proton events with energies >10Mev and solar radio bursts during the four-year period from 1997 November to 2000 November. We examine 28 solar proton events and their corresponding solar radio bursts at 15400, 8800, 4995, 2695, 1415, 606, 410 and 245 MHz. The statistical result shows that there is a close association between solar proton events and ≥3 solar radio bursts occurring at several frequencies, one or two days before. In particular, it is noteworthy that proton events occurring 相似文献
15.
The ancient record“Tian-da-yi“(the sky darkened greatly )is identified with the solar eclipse on May 31,976BC.This identification is demonstrated in this paper through a palaeographic ,astronomical and chronological analysis,It is probably the earliest solar eclipse in Chinese histroy that can be so identified. 相似文献
16.
利用“多云模型”方法,从云南天文台二维多波段太阳光谱仪观测到的Ｈβ光谱资料中导出１９８９年８月１７日太阳西边缘的一个大的耀斑环系不同时间的视向速度场．为了解释观测速度场的主要特征,本文采用如下假设和近似：环内物质在太阳重力、磁场应力和环内气压梯度力联合作用下由环足沿螺旋磁力线上升运动．应用ＭＨＤ理论计算了它的理论速度场．通过两者的比较发现,计算出的速度场与第一时段的观测速度场基本相似,这似乎对耀斑物质蒸发模型提供了支持． 相似文献
17.
Yu-Qin Chen Gang Zhao Jian-Rong ShiNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2002,2(5):419-428
We have calculated the orbital parameters for 90 stars in Chen et al. and updated the kinematic data for stars in Edvardsson et al. by using the accurate Hipparcos parallaxes and proper motions, and recalculated the \\\\\\\\\\\\-element abundances in Edvardsson et al. in a way consistent with Chen et al. The two sets of data are combined in a study of stellar populations and characteristics of F & G stars in the solar neighborhood. We confirm the result of Chen et al. that a distinguishable group of stars may belong to the thick disk rather than the thin disk. The ages for the stars are determined using the theoretical isochrones of VandenBerg et al. The age-metallicity relation is investigated for different subgroups according to distance from the sun and galactic orbital parameters. It is found that a mixing of stars with different orbital parameters significantly affect the age-metallicity relation for the disk. Stars with orbits confined to the solar circle all have metallicities [Fe/H] > -0.3 irresp 相似文献
18.
Jian Li Li-Yong Zhou Yi-Sui Sun Department of Astronomy Nanjing University Nanjing 《中国天文和天体物理学报》2006,6(5)
The orbital migration of Jovian planets is believed to have played an important role in shaping the Kuiper Belt. We investigate the effects of the long time-scale (2×107 yr) migration of Jovian planets on the orbital evolution of massless test particles that are initially located beyond 28 AU. Because of the slowness of the migration, Neptune's mean motion resonances capture test particles very efficiently. Taking into account the stochastic behavior during the planetary migration and for proper parameter values, the resulting concentration of objects in the 3:2 resonance is prominent, while very few objects enter the 2:1 resonance, thus matching the observed Kuiper Belt objects very well. We also find that such a long time-scale migration is favorable for exciting the inclinations of the test particles, because it makes the secular resonance possible to operate during the migration. Our analyses show that the v8 secular resonance excites the eccentricities of some test particles, so decreasing their perihelion distances, leading to close encounters with Neptune, which can then pump the inclinations up to 20℃. 相似文献