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51.
Zhang Chun-sheng 《紫金山天文台台刊》1998,(2)
The results of photographic observations of Comet Hale-Bopp made at Qingdao Station of Purple Mountain Observatory during the period from September to November of 1996 are given. It is shown that three events of outburst occurred on Sept. 24, Oct. 26 and Nov. 13, and a large jet appeared in the plate of Sept.23,1996. 相似文献
52.
中国科学院紫金山天文台青岛观象台从1996年4月开始到1995年5月1日结束,在138个观测夜,共拍摄Hale-Bopp彗星底片508张。发现:Hale-Bopp彗星在1996年9月24日的一次爆发,1996年10月26日,11月13日的两次可能爆发。在1996年9月23日的底片上,Hale-Bopp呈现巨大的喷流。在1997年2月8日至5月1日期间,Hale-Bopp彗星彗头内存在大量壳层结构。 相似文献
53.
P. P. Korsun 《Astronomische Nachrichten》1995,316(4):255-260
Spectroscopic observations of Comet P/Brorsen-Metcalf were made on August 9–13, 1989. Spatial profiles extracted from long-slit spectra were analyzed to determine the lifetimes of C3 and NH2 radicals and their parents, as well as the tailward acceleration of these radicals. In our investigations we used a Monte Carlo model. The average lifetime for C3 has been found to be 6.3 × 104 s and that for the parent of C3 to 6 × 103 s. The spatial profiles of C3 were almost symmetric and we need only 0.1 cm s−2 as the tailward acceleration. According to our simulations, C3H4 (allene) can be considered as the parent for C3. We obtained the average value 7.6 × 104 s for the lifetime of NH2 and 1.1 × 104 s for the lifetime of the NH2 parent. The tailward acceleration of NH2 was not more than 0.1 cm s−2. This result does not exceed the latest theoretical calculations of NH2 and NH3 lifetimes by a factor of 1.4. So, NH3 may be considered as a parent for NH2 in the atmosphere of P/Brorsen-Metcalf. 相似文献
54.
H.-U. Kaeufl T. Bonev H. Boehnhardt Y. R. Fernandez C. Lisse 《Earth, Moon, and Planets》2005,97(3-4):331-339
Comet 9P/Tempel 1, the target of the Deep Impact mission, has been intensively observed for a long time period before the encounter. Pre-impact ground based monitoring of the comet was an important prerequisite for the success of the first space experiment in which a comet is treated by an artificial impact. It provided the background data needed to disentangle the features caused by the impact from variations caused by the natural activity of the comet. In this paper we present results from the ESO-monitoring of the comet, conducted in the thermal infrared and optical spectral ranges during several months before the Deep Impact encounter with the comet. 相似文献
55.
Paul D. Feldman Stephan R. McCandliss Harold A. Weaver Michael J.S. Belton 《Icarus》2007,187(1):113-122
We report on the Hubble Space Telescope program to observe periodic Comet 9P/Tempel 1 in conjunction with NASA's Deep Impact Mission. Our objectives were to study the generation and evolution of the coma resulting from the impact and to obtain wide-band images of the visual outburst generated by the impact. Two observing campaigns utilizing a total of 17 HST orbits were carried out: the first occurred on 2005 June 13-14 and fortuitously recorded the appearance of a new, short-lived fan in the sunward direction on June 14. The principal campaign began two days before impact and was followed by contiguous orbits through impact plus several hours and then snapshots one, seven, and twelve days later. All of the observations were made using the Advanced Camera for Surveys (ACS). For imaging, the ACS High Resolution Channel (HRC) provides a spatial resolution of 36 km (16 km pixel−1) at the comet at the time of impact. Baseline images of the comet, made prior to impact, photometrically resolved the comet's nucleus. The derived diameter, 6.1 km, is in excellent agreement with the 6.0±0.2 km diameter derived from the spacecraft imagers. Following the impact, the HRC images illustrate the temporal and spatial evolution of the ejecta cloud and allow for a determination of its expansion velocity distribution. One day after impact the ejecta cloud had passed out of the field-of-view of the HRC. 相似文献
56.
Henry Florence Bockelée-Morvan Dominique Crovisier Jacques Wink Jörn 《Earth, Moon, and Planets》2002,90(1-4):57-60
CO was observed on March 11, 1997 in comet Hale–Bopp with theIRAM Plateau de Bure interferometer. The maps show evidence for
asymmetrical patterns, due to the Existence of CO jets. Analysis of the spectra and their velocity shifts shows that there
is a spiral CO jet rotating in a plane almost perpendicular to the sky plane.This is the first time that rotating jets are
observed for parent molecules.We have developed a 3-D model simulating rotating spiral jets of CO gas.We present here the
comparison between the observations and our model. 相似文献
57.
Between July 1996 and April 1997, 92 spectra of comet Hale-Bopp were obtained with the 6-meter BTA telescope of the SAO of
the RAS at Mount Pastukhov. The spectra are two-dimensional, which allows one to determine the energy distribution for each
emission along the slit and the energy distribution in wavelength for each individual position in the slit. From the 92 two-dimensional
spectra covering the inner coma, detailed spectral maps of the total near-nuclear region of the comet are available for July
10, 11 and 12, 1996 and April 15, 1997. We propose an hypothesis about an unknown cometary species near λ = 620 nm in the
spectrum obtained July 10, 1996. We also find an effect which may be caused by fluorescence of cometary dust.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
58.
Ichiro Hasegawa Syuichi Nakano 《Monthly notices of the Royal Astronomical Society》2003,345(3):883-888
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
59.
As a part of ESA's cornerstone mission ``ROSETTA' to comet 46P/Wirtanen a 100 kgLander will bring a scientific payload of
almost 27 kg to the surface of the nucleus.After a first scientific sequence it will operate for a considerable fraction of
thecometary orbit around the sun (between 3 AU and 2 AU). Ten experiments with a number of sub-experiments are foreseen; this
paper presents the current status of the Lander development and reviews the scientific capabilities of each of the experiments
at a time when the Flight Model (FM) of the Lander is already delivered. 相似文献
60.
We have constructed line-by-line fluorescence models for the ro-vibrational bands of the B-X system of sulfur dimers (S2). For the first time the detailed rotational lines of the bands are clearly resolved in the high-resolution echelle spectra of Comet Hyakutake (C/1996 B2), which were obtained at the Kitt Peak 4-m telescope on 26.4 March 1996 (UT). In order to construct satisfactory band models of the B-X system, we first compared the models to laboratory spectra available in literature, and then compared the models including Swings effects to the high-resolution spectra of Hyakutake. From the model fits, we derived a rotational temperature of 70±10 K, which should represent a temperature of a coma region close to the nucleus, where most of the S2 emissions originate. We present previously proposed scenarios for the origin of S2 in cometary comae, and compare them with our spectral analysis. 相似文献