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1.
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   

2.
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   

3.
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   

4.
利用日本“Yohkoh”卫星的资料及北京天文台2840MHz的射电观测资料,对1992年6月7日的太阳爆发事件进行了分析,结果表明,在这次爆发的脉冲相期间存在着大小两种时间尺度的脉动分量,大尺度的脉动周期约为30s,小尺度脉动周期为1-4s。利用硬X射线成像观测结果,发现大尺度的脉动与硬X射线源区的一系列变化相对应。文中给出了一个环-环相互作用的MHD振荡调制物理图像。  相似文献   

5.
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   

6.
综述了背景光源(类星体)与前方天体(星系、星系团等)成协的观测和统计事例.详尽叙述了与成协问题相关的引力透镜理论.全面介绍了对各种成协事例进行引力透镜理论解释的方法、研究现状及存在的问题.还给出了一种计算成协样品中面密度超出因子的改进方法.  相似文献   

7.
本系列文章中给出了谱线形成深度理论的发展特别是其最新进展,分别叙述了与此理论相联系的贡献函数和响应函数的演化过程,讨论了此理论的应用特别是用于太阳矢量磁场空间三维结构的推导.在这第一篇文章中,叙述了与贡献函数相夫的理论,指出了应用此理论的局限性,并讨论了唯一性问题.  相似文献   

8.
本文作者用澳大利亚Parkes64m射电望远镜观测了OH17.7-2.0的拱星OH脉泽辐射。在观测中共测得了三个峰,其中一个峰是我们新发现的弱源,两个峰是过去发现的强源。用二维Gaussian拟合我们发现强源位置与一个IRAS点源位置相一致,弱源位置在这个IRAS点源位置的西南方。强源的两个峰的速度位置和峰值流量密度都是比较稳定的。  相似文献   

9.
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   

10.
利用日本YOHKOH卫星HXT提供的HXR爆发资料,和中国科学院北京天文台的太阳射电宽频带动态频谱仪(10-2.0GHZ,2.6-3.8GHZ)提供的微波爆发资料,对共生事件进行了初步统计分析,并对其中两例典型事件:1997年11月28日0503UT事件及1998年5月9日0340UT事件与共生的HXR爆发进行了详细比较,给出了几点有意义的结果及理论解释.  相似文献   

11.
The orbit of Comet C/2002C1 (Ikeya–Zhang) has a similarity to that of Comet C/1661C1 (Hevelius), and the numerical integration of the motion of C/2002C1 backward shows a possible linkage of those two comets. Thus, 153P/Ikeya–Zhang was designated a periodic comet. Historical records of comets in 877 and 1273 are also identified with Comet 153P/Ikeya–Zhang. The integrated orbital elements during 77 and 2362, and historical records of the comet are also presented and discussed.  相似文献   

12.
Comet 15P/Finlay is unusual in that, contrary to ab initio expectations, it demonstrates no apparent linkage to any known meteor shower. Using data contained within the Electronic Atlas of Dynamical Evolutions of Short-Period Comets, we evaluate theoretical shower radiants for Comet 15P/Finlay, but find no evidence to link it to any meteoric anomalies in recorded antiquity. This result, however, must be tempered by the fact that any Comet 15P/Finlay-derived meteoroids will have a low, 16 km s−1, encounter velocity with Earth's atmosphere. Typically, therefore, one would expect mostly faint meteors to be produced during an encounter with a Comet 15P/Finlay-derived meteoroid stream. We have conducted a D -criterion survey of meteoroid orbits derived from three southern hemisphere meteor radar surveys conducted during the 1960s, and again we find no evidence for any Comet 15P/Finlay-related activity. Numerical calculations following the orbital evolution of hypothetical meteoroids ejected from the comet, at each perihelion epoch since 1886, indicate that Jovian perturbations effectively 'drive' the meteoroids to orbits with nodal points beyond the Earth's orbit. The numerical calculations indicate that, even if Comet 15P/Finlay had been a copious emitter of meteoroids during the past 100 years, virtually none of them would have evolved into orbits capable of being sampled by the Earth. There are good observational data, however, to suggest that Comet 15P/Finlay is becoming a transitional comet–asteroid object, and that it has probably not been an efficient producer of meteoroids during the past several hundreds of years.  相似文献   

13.
包纲  陈道汉  马月华 《天文学报》2004,45(3):279-287
苏梅克-列维9号彗星(SL9)与木星相撞后,在木星上观测到的以常速度(~450m/s)向外扩展的圆环意味着这是碰撞在木星大气中引起的线性波动.我们选取:非旋转、无粘性、密度分层、不可压缩的木星大气模型,而且木星大气以水平速度U=b az运动;给出初始扰动压力P(r;0)作为碰撞的初始条件,用流体力学方程组求解了彗木相撞中的惯性引力波.结果表明:当木星大气以速度U=U0(~170m/s)运动时,彗星碎片的大部分能量都用来产生内波,同时还得到彗星碎片的撞击深度H与水平相速Vp的关系式.当木星大气以速度为U=b az运动时,木星大气的扰动能量不再是在动能和势能间均分。  相似文献   

14.
The possibility of impacts between comets belonging to the Jupiter Family and other small bodies orbiting in the main asteroid belt, and the consequences in relation to cometary activity are discussed. The probability of such events and the jumps in cometary brightness caused by impacts are examined. The results are compared with the results of the Deep Impact mission to Comet 9P/Tempel 1. The main conclusion of this paper is in agreement with previous findings, namely that an impact mechanism cannot be the main cause of the outburst activity of comets.  相似文献   

15.
Near-infrared and mid-infrared observations of the site of the 2009 July 19 impact of an unknown object with Jupiter were obtained within days of the event. The observations were used to assess the properties of a particulate debris field, elevated temperatures, and the extent of ammonia gas redistributed from the troposphere into Jupiter’s stratosphere. The impact strongly influenced the atmosphere in a central region, as well as having weaker effects in a separate field to its west, similar to the Comet Shoemaker-Levy 9 (SL9) impact sites in 1994. Temperatures were elevated by as much as 6 K at pressures of about 50-70 mbar in Jupiter’s lower stratosphere near the center of the impact site, but no changes above the noise level (1 K) were observed in the upper stratosphere at atmospheric pressures less than ∼1 mbar. The impact transported at least ∼2 × 1015 g of gas from the troposphere to the stratosphere, an amount less than derived for the SL9 C fragment impact. From thermal heating and mass-transport considerations, the diameter of the impactor was roughly in the range of 200-500 m, assuming a mean density of 2.5 g/cm3. Models with temperature perturbations and ammonia redistribution alone are unable to fit the observed thermal emission; non-gray emission from particulate emission is needed. Mid-infrared spectroscopy of material delivered by the impacting body implies that, in addition to a silicate component, it contains a strong signature that is consistent with silica, distinguishing it from SL9, which contained no evidence for silica. Because no comet has a significant abundance of silica, this result is more consistent with a “rocky” or “asteroidal” origin for the impactor than an “icy” or “cometary” one. This is surprising because the only objects generally considered likely to collide with Jupiter and its satellites are Jupiter-Family Comets, whose populations appear to be orders of magnitude larger than the Jupiter-encountering asteroids. Nonetheless, our conclusion that there is good evidence for at least a major asteroidal component of the impactor composition is also consistent both with constraints on the geometry of the impactor and with results of contemporaneous Hubble Space Telescope observations. If the impact was not simply a statistical fluke, then our conclusion that the impactor contained more rocky material than was the case for the desiccated Comet SL9 implies a larger population of Jupiter-crossing asteroidal bodies than previously estimated, an asteroidal component within the Jupiter-Family Comet population, or compositional differentiation within these bodies.  相似文献   

16.
Orbits are calculated for Comet C/1845 L1 (the Great June Comet) and C/1846 D1 (de Vico), the former based on 157 observations in right ascension and 152 in declination and the latter on 10 and 9, respectively. Both orbits are hyperbolic and statistically distinguishable from parabolas. Statistical tests indicate that the residuals are random and thus the orbits satisfactory. The Great June Comet is in no way associated with the comet Tycho Brahe observed in 1596 (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

17.
M. Weiler  H. Rauer  J. Knollenberg 《Icarus》2007,190(2):423-431
The target of the Deep Impact space mission (NASA), Comet 9P/Tempel 1, was observed from two nights before impact to eight nights after impact using the FORS spectrographs at the ESO VLT UT1 and UT2 telescopes. Low resolution optical long-slit spectra were obtained to study the evolution of the gas coma around the Deep Impact event. Following first results of this observing campaign on the CN and dust activity [Rauer, H., Weiler, M., Sterken, C., Jehin, E., Knollenberg, J., Hainaut, O., 2006. Astron. Astrophys. 459, 257-263], this work presents a study of the complete dataset on CN, C2, C3, and NH2 activity of Comet 9P/Tempel 1. An extended impact gas cloud was observed moving radially outwards. No compositional differences between this impact cloud and the undisturbed coma were found as far as the observed radicals are concerned. The gas production rates before and well after impact indicate no change in the cometary activity on an intermediate time scale. Over the observing period, the activity of Comet 9P/Tempel 1 was found to be related to the rotation of the cometary nucleus. The rotational lightcurve for different gaseous species provides indications for compositional differences among different parts of the nucleus surface.  相似文献   

18.
本文给出了1994年7月17日至22日,彗星碰撞期间,福州和乌鲁木齐两个观测点所取得的部分光学观测资料。  相似文献   

19.
A revised linear model is presented to explain the waves from the collisions of Comet Shoemaker-Levy 9 with Jupiter, in which the Jovian atmosphere is taken as a rotating stratified, compressible and inviscid fluid layer. It is shown that the effect of compressibility can not be ignored, although most of the impacting energy is still converted into the energy of internal waves.  相似文献   

20.
We have fitted ∼200 RXTE and INTEGRAL spectra of the neutron star (NS) low-mass X-ray binary (LMXB) GX 9+9 from 2002 to 2007 with a model consisting of a disc blackbody and another blackbody representing the spreading layer (SL), i.e. an extended accretion zone on the NS surface as opposed to the more traditional disc-like boundary layer. Contrary to theory, the SL temperature was seen to increase towards low SL luminosities, while the approximate angular extent had a nearly linear luminosity dependency. Comptonization was not required to adequately fit these spectra. Together with the ∼ 70° upper bound of inclination implied by the lack of eclipses, the best-fitting normalization of the accretion disc blackbody component implies a distance of ∼10 kpc, instead of the usually quoted 5 kpc.  相似文献   

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