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1.
J.R. De Laeter 《Meteoritics & planetary science》1982,17(3):135-140
Two new iron meteorites from Western Australia are described: Cosmo Newberry — a 2.156 kg meteorite of unusual spiky shape, and Gnowangerup — a 33.6 kg pear-shaped meteorite. X-ray fluorescence spectrometry shows that Cosmo Newberry can be classified in Group IIA, whilst Gnowangerup is a member of Group IIIAB. Neither iron can be associated with any other Western Australian meteorite. 相似文献
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The Indonesian meteorites, Selakopi, an H-5 chondrite, and Glanggang, a breccia with H-6 fragments is an H-5 chondritic matrix, were recovered on the same day from sites only 50 km apart. The textures and compositions of Selakopi and the H-5 portion of Glanggang are very similar, indicating that they are closely related. The bulk chemistry of the H-6 portion of Glanggang is also very similar to that of the samples mentioned. It has therefore been concluded that Selakopi and the Glanggang breccia fragments were derived from the same source area and were probably ejected at the same time. Minor differences in bulk composition and texture among the three samples may be attributed to local variations on the parent body. However, for reasons stipulated in the conclusion, we recommend that separate names be maintained for these meteorites until further, more definitive investigations have been made. 相似文献
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Alan E. Rubin G. Jeffrey Taylor Klaus Keil Gordon Nelson 《Meteoritics & planetary science》1981,16(1):9-12
Two new ordinary chondrites were found about 40 km west of Albuquerque, New Mexico. Correo is an H4 chondrite with distinct chondrules and major olivine (Fo81.4), orthopyroxene (En82.3) and plagioclase (An12). Suwanee Spring is an L5 chondrite with few distinct chondrules and a highly recrystallized matrix. Major minerals are olivine (Fo75.4), orthopyroxene (En77.7) and plagioclase (An9). The metallic Ni-Fe phases of both meteorites are typical of slowly-cooled ordinary chondrites. 相似文献
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Australites have been found embedded in ferruginous grit and silcrete in the Eastern Goldfields region of Western Australia. 相似文献
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本文描述NOAA6233活动区中的一组双带耀斑及和与之有时间相关性的NOAA6240中的单带耀斑的磁场位形.并着重讨论由观测推断出的磁场拓扑联接性.分析表明:三个单耀斑发生在正极磁区里,与发生在δ黑子区中的双带耀斑,可能有远距离磁环相联系.这一高位磁环与δ黑子中的低位剪切磁环柑互作用,可能是能发双带耀斑的直接原因.在双带耀斑能量初始释放中被加速的电子,可能是沿着高位磁环或磁拓扑分界面(NOAA 6240与NOAA6233间)传播,并导致NOAA6240中的单带耀斑.因此这些单带耀斑都可能是双带耀斑的相应耀斑. 相似文献
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利用上海天文台佘山40 厘米折射望远镜拍摄的2 个底片天区15 张照相底片上的31 次观测,以ACT 星表作为初始参考星表,按中心重叠法进行归算处理,得到了16 颗依巴谷星和38 颗场星的高精度位置和自行结果,其中依巴谷星的赤经和赤纬标准误差的平均值分别为10 .5 mas 和7 .5 mas,赤经自行和赤纬自行标准误差的平均值分别为0 .70 mas/yr 和0 .59 mas/yr 相似文献
7.
徐继鸿 《中国科学院上海天文台年刊》2002,(1)
概述了制约线性多步积分公式轨道积分状态的多种因素 ;提出了综合评价线性多步积分公式积分性能的两项新指标。建议在对数值计算有较高精度要求的科研项目中 ,应将构造并选择适合研究项目的线性多步积分公式以及高效的积分方式列为课题前期工作的重要部分 相似文献
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John H. Puffer 《Meteoritics & planetary science》1974,9(4):281-288
Spherules composed of magnetite were found throughout the state of New Jersey. Samples of coastal plain sands of Miocene age, beach sands, street sweepings, wind-blown dust, river waters, and dust from the stack scrubber of a scrap iron foundry were carefully examined. Spherules were found in each of the samples representing recent environments and in ancient sediments sampled near the surface, but are absent from each of the wide variety of ancient sediments carefully sampled below about one meter. The spherule samples consistently contain 0.4–0.8 weight percent Mn but contain less than 0.1 weight percent Ni. It is concluded that virtually none of the spherules is of an extraterrestrial origin. 相似文献
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In April 1969, the chondrite was accidentally found in the side wall of the vegetable storage excavated at Shibayama-machi, Sanbu-gun, Chiba-ken, Japan, by Mr. A. Ishii and his grandson, Mr. S. Ito. The chondrite named Shibayama has been weathered thoroughly for a long period of burial underground. The bulk chemical composition, especially total Fe (21.41%) and ratios of Fetotal/SiO2(0.557), SiO2/MgO (1.59) and molar composition of olivine (Fa23) and pyroxene (Fs22) as well as mineral composition, indicate that Shibayama is a typical olivine-hypersthene chondrite. If the oxidized Fe is assumed only from metallic Fe, the original metallic Fe (7.75%) and Femetal/Fetotal(0.361) also support the above conclusion. From the well-recrystallized texture, indistinct and obliterated chondrule-matrix boundary, homogeneous composition of olivine and pyroxene, absence of igneous glass, and interstitial and well-developed plagioclase, this chondrite could be classified in petrologic type 6. Mosaic texture, kink bands, undulatory extinction of silicate grains and maskelynitization of plagioclase indicate that Shibayama suffered from a heavy shock effect, as is seen in other L-6 group chondrites. 相似文献
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利用多普勒资料进行轨道改进,将遇到卫星信标机和测站接收机的频偏带来的系统差,如何估计各站圈的频偏,是决定定轨精度的一个关键问题.文[1]中提出的Guier导航计算频偏的方法,实践表明是行之有效的.但是,Guier导航计算较复杂,在用数值积分计算星历表的软件中,使用这一算法比较困难.提出一种基于法方程系数矩阵分块求逆的新算法,只需求6×6或7×7矩阵的逆,计算频偏十分简单.仿真表明,新算法的定轨精度近似达到C.R.下界一理论最佳精度,比Guier导航算法的精度高15%左右. 相似文献
12.
云南天文台高分辨率斑点成像的新进展 总被引:2,自引:0,他引:2
本文报道了对天文目标:双星ADS16800、ADS16173,三星Hu66(ADS11344)和Hld171(ADS16648)进行的斑点成像观测及测量结果。介绍了所用的二维光子计数斑点像探测系统的性能,分析了探测系统的光子噪声、附加噪声和其它更复杂的噪声对斑点图的平均功率谱和重谱的影响。在讨论了改正重谱中的噪声偏差项时提出了对重谱基底施加正性约束的算法。测量的结果表明,实现了高精度的微射受限天文 相似文献
13.
李元杰 《中国天文和天体物理学报》1990,(1)
本文指出一种弯曲时空释放引力能的新机制,它不同于Penrose过程、Starobinsky-Unruh过程,也不同于Hawking蒸发过程。具体以Kerr和Schwarzschild度规为例,证实这种机制的存在,并给出获得净能量的公式(18),(20)。 相似文献
14.
对XPer新发射相连续四年的光学光谱和近红外光度监测结果,XPer近两年的变化不同寻常,主要表现以下两点:(1)尽管它的光学光度V星等只恢复至失去气壳前的亮度,但Ha发射线等值宽度和近红外,J,H和K光度地超过了历史记录的最大值,分别达到了16.34A和5.3^m,5.3^m和5.1^m,表明XPer新发射相气南的密度和尺度较都大,(2)我们首次观测到XPer近红外光度和Hα发射线等值宽度变化趋势 相似文献
15.
Gennady P. Vdovykin 《Meteoritics & planetary science》1972,7(4):547-552
Based on its mineral composition and structure the Haverö meteorite, which fell on August 2, 1971, in Finland, is a ureilite, the sixth meteorite in this rare group. Elementary carbon in this meteorite is represented by diamond, lonsdaleite, graphite and chaoite microcrystals in the intergrowths. The presence of lonsdaleite and chaoite indicates that diamonds were formed in the Haverö meteorite due to the action of strong shock waves 相似文献
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The long-term modulation of galactic cosmic rays is investigated from 1957 up to 1992 analysing the dynamic and the quasi-stationary components, separately. It has been found that the dynamic component is characterized by the presence of two peaks at the maximum phase of each solar activity cycle. We infer that the time interval between the two peaks corresponds to a period (well-related to the polar heliomagnetic reversal) in which somewhat decreased activity occurs for intense and long-lasting solar events. In fact, a contemporary dip in the magnetic energy released from the Sun was observed, in agreement with the suggested double maximum displayed by the basic features of the 11-year solar-activity cycle (Gnevyshev, 1977, and references therein). Moreover, the dynamic component of cosmic-ray modulation often shows a multi-structured profile in both peaks of activity, fairly well-connected with the pattern of the green corona brightness. On the other hand, analysing the quasi-stationary long-term trend of cosmic-ray intensity we pick out a good relationship between periods of enhanced cosmic-ray modulation and the area expansion of coronal intensity levels. The relevance of our results for solar-terrestrial forecasting is underlined. 相似文献
18.
本文通过统计比较,并用更完善的模型作成员概率的最大似然估计,对昂星团天区耀星的成员性进行了新的细致的讨论,指出Mirzoyan等根据Jones的自行成员概率估计得出的非成员耀星呈现向团心集中强烈趋势的现象,是由于Jones对成员星成员概率的普遍低估以及对外围恒星成员概率的一定程度高估加上在中心附近观测误差和错误显著增加而造成的.本文根据Stauffer等对更完整的样本估计的成员概率,以其中成员概率大于0.5的星为成员星,重新计算了昂星团内成员耀星在红矮星中占的比例(相对数量),表明了相对数量在MV<8.0时随星等变暗而增大,而MV≈8.0时开始稳定在64%左右,直至样本完整性的极限(MV≈11.5).因此,昂星团内无明显耀发活动的红矮星占该星团内红矮星总数的1/3左右或更少. 相似文献
19.
《Meteoritics & planetary science》1975,10(2):188-188
Carbonaceous Meteorites by Bartholomew Nagy with a preface by Harold Urey, Elsevier Scientific Publishing Company, 1975, Amsterdam, The Netherlands. 746 pages, US $80.95. Monograph on the classification, composition ages, falls and origin of meteorites with emphasis on historical information regarding carbonaceous chondrites and their chemistry, mineralogy and petrology. Meteorites A nd Their Origins by G. J. H. McCall, John Wiley & Sons, 1973, New York, USA. 352 pages, US $12.95. Reviews all aspects of meteoritics including craters and tektites. Meteorites — Classification and Properties by J. T. Wasson, Springer-Verlag, 1974, New York, Heidelberg, Berlin. 316 pages, US $31.20. An introduction to meteorite science and a handbook on meteorite classification. 相似文献
20.
俞志尧 《中国科学院上海天文台年刊》2002,(1)
利用法国巴黎天文台的南锡射电望远镜对ON2西部区域OH16 12MHz脉泽首次进行观测 ,观测结果表明 ,西部区域的OH16 12MHz脉泽的辐射频谱为典型的单峰结构。结合模型对西部区域的OH16 12MHz脉泽谱线频谱图进行分析和研究。利用薄盘模型 ,得到相应于ON2西部区域的OH16 12MHz脉泽单峰脉泽斑的位置在r =112 .5AU ,Y =7.6AU ,其Keplerian运动速度为Ur=10 .6km s ,Vt =- 9.4km s . 相似文献