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In combination with the authors' previous observation about the splitting of Comet Halley in March 1986,the events involving the sharp,straight feature in the antisolar direction observed in the head of Cornet halley in 1910 (such as those occurring on May 14,25 and 31,and June 2) are redis-cussed.The analysis leads to the following scenario;When comet Halley explodes and splits,a fragment jettisoned or thrown off from the nucleus will,after moving in the direction of its tail,develop into a mini-comet.Although not weel developed or permanent,it has its own plasma tail and,sometimes,a dust tail.If Bobrovnikoff's definition of a secondary nucleus is assumed,then the fragment should be considered as a real secondary nucleus.It seems that the current idea of a tailward jet suggested by Sekanina and Larson is a wrong explanation for the plasma tail of a mini-comet and hence the rotation period of 52-53h for Comet Halley is doubtful. 相似文献
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《Chinese Astronomy and Astrophysics》1987,11(4):307-308
We report that during our photoelectric photometric narrowband monitoring of Comet Halley during 1986 Mar 20 – Apr 3, we witnessed a considerable explosion on the comet. 相似文献
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Szegö Karoly Crifo Jean-François Rodionov Alexander V. Fulle Marco 《Earth, Moon, and Planets》2002,90(1-4):435-443
The cameras carried onboard the flyby missions to comet P/Halleyin 1986 imaged the near nuclear jet activity fromseveral spatial
directions. The observed, very structured near nucleardust jets were considered at that timeas the result of dust emission
from well localized active surface regions(without supporting 3-D model computations, however).Based on the first, recently
developed 3-D gas dynamical model ofP/Halley's activity,we have been shown that jet features can be reproduced assuming ahomogeneous
dusty icenucleus surface. The dust in the collisional near nuclear comais concentrated along the gas flow discontinuities
resulting from thecomplicated surface orography, creating the visual impression ofdust jets. We present here the results of
these calculations forthe near nucleus dust distributions,and we compare them with the direct observations made during thethree
Halley flybys (Vega 1, Vega 2, and Giotto). 相似文献
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Results of the analysis of the Comet Halley spectrophotometry,which has been carried out by H.K. Nazarchuk in 1985 with the
TVscanner of the 6-meter telescope (SAO, Russia) are presented. Timevariations in the intensities of the CN, CH, C2 and NH2bands were investigated using the series of spectra obtained inthe spectral region λλ=410÷ 510 nm. Theauto-correlation functions
for all the bands, thecross-correlation functions for C2 lines and their Fouriertransformations are calculated to determine the frequencies andperiods of the variations. A possibility
is considered thathigh-amplitude fast variations of spectral lines in Comet Halleyare caused by solar flares. The daily numbers
of solar spots andproton fluxes with energies of more then 1 MeV are compared withthe spectral variations of these lines.
It is shown that in theobservation periods the comet was projected onto an active regionof the Sun, but, among all the kinds
of solar activity, mainlythe solar proton flux with energies less than 4 MeV coincides intime with fast intensity variations
in the spectral lines. Analgorithm of cross-correlation analysis of discrete samplingseries with gaps is built, and average
cross-correlation coefficientsare calculated. 相似文献
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哈雷彗星在日彗距较大时出现长而直的主彗尾(尾流),这是很有趣的。尾流一般是指等离子体尾流;但是,当地球接近彗星轨道面时,尘埃尾流可能叠加到主彗尾上。在一般感光波段宽的彗星底片上很难区分这两种尾流。本文选取哈雷彗星在不同日彗距的5条主尾流,作了光度测量和比较分析。得出沿各尾轴及其垂直方向几个截面的亮度分布、亮度半极大全宽、尾轴的视风差角和真风差角及彗尾长度。在所分析的蓝敏底片上,过近日点前的2个尾流肯定是等离子体尾流,而5个尾流的相似性以及其他证据说明它们主要都是等离子体尾流,尘埃彗尾的污染是次要的。 相似文献
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Chen Pei-sheng Gao Heng Zhang Yun Chen Yan-kang Yang Jing Mei Mani 《Chinese Astronomy and Astrophysics》1987,11(4):309-311
We report on our photometric and spectrophotmetric measurement of Comet Halley in near infrared. The observations confirmed the explosion found in the preceding article and showed the post-explosion behaviour of the comet was different in the visible and the infrared. Water emission lines at 1.4 cm and 1.9 cm were found. 相似文献
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《Chinese Astronomy and Astrophysics》1987,11(1):38-40
We give 15 accurate positions of Comet Halley (1982i) at an early time (1984 November) of the present return, obtained with a CCD camera on a 1-metre telescope. The internal accuracies are ±0.0295s, ±0.27; the external accuracies, ±0.196s, ±2.20. 相似文献
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Comet P/Halley has been observed during its approach to perihelion at heliocentric distancesR = 11.0 AU and R = 8.2 AU. No extended coma is seen and limits can be placed on the fraction of the total light contributed by coma. The brightness of the comet varies on a short time scale. The variations may be due to transient activity or to rotation of the irregular nucleus. 相似文献
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本文主要论述用25米射电望远镜和自相关频谱仪于1986年4月13—17日(UT)期间在我国陕西眉县首次对哈雷彗星羟基分子1667 MHz射电话线的观测及归算结果。由谱线轮廓的幅度、宽度、形状和面积相继导出的谱线强度为-2.4Jy,膨胀速度为0.92kms~(-1),速度的一级矩为0.20kms~(-1),以及羟基的母分子产生率为1.7×10~(29)mols~(-1)。文中所给出的宇宙羟基源W3和W12的观测结果,分别用来检验设备系统探测射电谱线的功能及对哈雷彗星的羟基谱线进行强度定标。这些结果均同理论预期或以往的有关观测相符合。 相似文献
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S. C. Joshi J. B. Srivastava C. D. Kandpal T. D. Padalia B. B. Sanwal U. S. Chaubey M. Singh 《Earth, Moon, and Planets》1987,38(3):249-252
Positions of Comet Halley have been measured from the photographic plates taken at Cassegrain focus of the 104-cm telescope of Uttar Pradesh State Observatory. 相似文献
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Alexander I. Ershkovich 《Earth, Moon, and Planets》1981,25(4):521-522
The method of evaluation of the cometary magnetic field proposed by Podgornyet al. (1980) is shown not to be self-consistent. An alternative method is discussed. 相似文献
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P. S. Goraya B. S. Rautela B. B. Sanwal S. K. Gupta H. K. Duggal J. S. Malhi 《Earth, Moon, and Planets》1989,45(1):17-27
Spectral scans of the head of periodic Comet Halley (1982i) have been presented and analysed in detail in the optical region (3200–7000 Å); for ten nights during pre-perihelion period. Emission features due to NH, CN, CH, C3, and C2 molecules have been identified. The behaviour of the variation of different emission lines strength as a function of heliocentric distance has been investigated. It is found that the comet exhibits night-to-night variation of brightness. The abundances and production rates of CN and C2 species have also been derived. 相似文献
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《Icarus》1987,70(2):264-268
We used the VLA2 to search for continuum emission from icy grains in a halo around Comet Halley in mid November 1985. We found the 3σ upper limit to the 2-cm flux density from the comet to be 1 × 10−4 Jy, which is consistent with the detections at 1.3 and 3.5 mm by W.J. Altenhoff et al. (1986, Astron. Astrophys., in press) only if the emission comes from particles which do not radiate efficiently at centimeter wavelengths. These particles could be slightly dirty submillimeter-sized icy grains or small refractory grains. 相似文献
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On November 15, 1985 a star was occulted by Comet Halley. Seven consequent spectra of the star has been obtained with 5-minute exposition with the TV scanner at 6-meter telescope. Simultaneously seven spectra of the cometary atmosphere were obtained at the projected distance 40” from the star. A method is developed to calculate the optical thickness of the cometary atmosphere as a function of wave length and the nucleocentric distance. This function is given in the spectral range 3925 Å−4850 Å. 相似文献
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Two photographs of Comet Halley in CN were obtained in 1986 April 8 and 12, and two in C3, on March 21 and May 5. Photometry led to mean brightness profiles of the CN and C3 comae on these days. Using Haser's coma model, the scale-heights of these two molecules and of the parent molecules were derived. 相似文献
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E. Jehin D. Bockelée-Morvan N. Dello Russo J. Manfroid D. Hutsemékers H. Kawakita H. Kobayashi R. Schulz A. Smette J. Stüwe M. Weiler C. Arpigny N. Biver A. Cochran J. Crovisier P. Magain H. Rauer H. Sana R. J. Vervack H. Weaver J.-M. Zucconi 《Earth, Moon, and Planets》2009,105(2-4):343-349
We report on simultaneous optical and infrared observations of the Halley Family comet 8P/Tuttle performed with the ESO Very Large Telescope. Such multi-wavelength and coordinated observations are a good example of what can be done to support space missions. From high resolution optical spectroscopy of the CN (0,0) 388 nm and NH2 (0,9,0) 610 nm bands using UVES at UT2 we determined 12C/13C = 90 ± 10 and 14N/15N = 150 ± 20 in CN and we derived a nuclear spin temperature of NH3 of 29 ± 1 K. These values are similar to those found in Oort-Cloud and Jupiter Family comets. From low resolution long slit spectroscopy with FORS1 at UT2 we determined the CN, C3 and C2 production rates and the parent and daughter scale lengths up to 5.2 105 km tailward. From high resolution IR spectroscopy with CRIRES at UT1 we measured simultaneously the production rates and mixing ratios of H2O, HCN, C2H2, CH4, C2H6, and CH3OH. 相似文献