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《天文学进展》编辑部 《天文学进展》2020,(1):120-120
一、本刊刊登反映国内外天文学研究的最新进展和作者见解的述评、研究论文、前沿介绍、专题讲座、研究快报。反映新思路、新手段、新成果的短评优先发表。二、来稿须包括:题名、作者署名、作者单位及所在地与邮政编码、摘要、关键词、正文、参考文献、英文摘要、英文关键词等。三、来稿应论点明确、叙述精练、条理清晰、深入浅出,以利非本分支学科的读者阅读。 相似文献
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《天文学进展》编辑部 《天文学进展》2014,(4)
<正>一、本刊刊登反映国内外天文学研究的最新进展和作者见解的述评、研究论文、前沿介绍、专题讲座、研究快报。反映新思路、新手段、新成果的短评优先发表。二、来稿须包括:题名、作者署名、作者单位及所在地与邮政编码、摘要、关键词、正文、参考文献、英文摘要、英文关键词等。三、来稿应论点明确、叙述精练、条理清晰、深入浅出,以利非本分支学科的读者阅读。四、摘要应简明扼要地概括正文中的主要信息。采用第三人称的写法,不用"本文"、"作者"等作主语。稿件如果以中文发表,英文摘要应有近一页的篇幅。五、关键词请尽可能参照ApJ.、MNRAS.和AA共同采用的关键词表选用,可适当 相似文献
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Abstract— To examine the thermal history of the parent body/bodies of equilibrated H chondrites, we treated data for 11 volatile trace elements (Co, Rb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, and In in order of putative volatility) in 90 falls: 15 H4; 46 H5, and 29 H6. Using univariate statistical tests, contents of few of these elements differ significantly between any two of these suites. One element, Cs, differs systematically between all three pairs of suites; Co and Tl differ between two pairs of suites. For Co and Cs, contents varied as H4 > H5 > H6; while for Tl, contents varied as H4 < H5 < H6. Using multivariate statistical tests, all three suites can be distinguished compositionally, with trace element contents in the H5 suite being intermediate to those of H4 and H6. Surprisingly, the multivariate distinguishability reflects contents of less volatile Co, Rb, Ag, Se and Cs, and not of highly volatile Te, Zn, Cd, Bi, Tl and In. The compositional trends apparently reflect heterogeneous accretion >600 K, with the suites deriving from a stratified parent body/bodies. 相似文献
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Two distinct assemblages of high‐pressure liquidus phases in shock veins of the Sixiangkou meteorite
Abstract— Shock‐produced complex veins, including earlier and later veins, are identified in the Sixiangkou L6 chondrite. The early vein is intersected by the late vein and consists of coarse‐grained aggregates of ringwoodite, majorite, and lingunite, and fragments of olivine, pyroxene, plagioclase, metal, and troilite, as well as a fine‐grained matrix of garnet, ringwoodite, metal, and troilite. The late vein mainly consists of a fine‐grained matrix of garnet, magnesiowüstite, metal, and troilite, as well as a small amount of coarse‐grained aggregates. The amount of fine‐grained matrix suggests that the late vein was nearly completely melted, whereas the early vein underwent partial melting. Both fine‐grained assemblages of garnet plus ringwoodite in the early vein and garnet plus magnesiowüstite in the late vein are liquidus phases crystallized from shock‐induced melt. Based on our understanding of the liquidus assemblages, the late vein experienced a higher pressure and temperature than the early vein. 相似文献
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It is shown that knowing the energy flux density of the radio emission, the rate of increase in the period, and the distance
of a pulsar enables one to calculate all the rest of its most important characteristics (the solid angle of the radio emission
beam, the radio luminosity, the solid angle of the beam of γ rays, the energy flux density of the g-ray emission, and the
magnetic moment, moment of inertia, and mass of the neutron star). Equations from which these pulsar characteristics can be
calculated are given at the end of the paper. The results of calculations for a number of pulsars are given in Tables 2 and
3 as an illustration.
Translated from Astrofizika, Vol. 43, No. 2, pp. 277-291, April–June, 2000. 相似文献
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M. A. Kazarian 《Astrophysics》2000,43(2):136-140
The results of spectroscopic observations of the nucleus of the S component of the galaxy Kaz 163, carried out on the 6-m
telescope of the Special Astronomical Observatory in 1982, are presented. The equivalent widths, relative intensities, and
half-widths of emission lines were determined. The electron temperature, electron density, and mass of the gaseous component
of the nucleus were also determined. The half-widths and equivalent widths varied almost twofold over the time of observations
from October 31, 1981, to May 28, 1982. During the same time the intensity of the [O III] λ 4363 auroral line increased fairly
strongly.
Translated from Astrofizika, Vol. 43, No. 2, pp. 183-189, April–June, 2000. 相似文献
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Gelys Trancho Bryan Miller Begoa García-Lorenzo Sebastin F. Snchez 《New Astronomy Reviews》2006,49(10-12):613
Studies of globular cluster systems play a critical role in our understanding of galaxy formation. Imaging with the Hubble Space Telescope has revealed that young star clusters are formed copiously in galaxy mergers, strengthening theories in which giant elliptical galaxies are formed by the merger of spirals [e.g. Whitmore, B.C., Schweizer, F., Leitherer, C., Borne, K., Robert, C., 1993. Astronomical Journal. 106, 1354; Miller, B.W., Whitmore, B.C., Schweizer, F., Fall, S.M., 1997. Astronomical Journal. 114, 2381; Zepf, S.E., Ashman, K.M., English, J., Freeman, K.C., Sharples, R.M., 1999. Astronomical Journal. 118, 752; Ashman, K.M., Zepf, S.E., 1992. Astrophysical Journal. 384, 50]. However, the formation and evolution of globular cluster systems is still not well understood. Ages and metallicities of the clusters are uncertain either because of degeneracy in the broad-band colors or due to variable reddening. Also, the luminosity function of the young clusters, which depends critically on the metallicities and ages of the clusters, appears to be single power-laws while the luminosity function of old clusters has a well-defined break. Either there is significant dynamical evolution of the cluster systems or metallicity affects the mass function of forming clusters. Spectroscopy of these clusters are needed to improve the metallicity and age measurements and to study the kinematics of young cluster systems. Therefore, we have obtained GMOS IFU data of 4 clusters in NGC1275. We will present preliminary results like metallicities, ages, and velocities of the star clusters from IFU spectroscopy. 相似文献
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M. Sobotka 《Astronomische Nachrichten》2003,324(4):369-373
Sunspots and pores appear as a consequence of interactions between strong magnetic fields and moving plasma. A wide variety of small‐scale features, presumably of convective origin, are observed in photospheric layers of sunspots and pores: Umbral dots, light bridges, penumbral filaments, and penumbral grains. Each type of features has specific morphological, photometric, spectral, and kinematic characteristics. Spots and pores modify velocity fields in adjacent photosphere and sub‐photospheric layers. Recent high‐resolution spectral, broad‐band, and helioseismic observations of the structure, dynamics, and magnetic fields of sunspots and pores, together with theoretical interpretations, are discussed in this review. 相似文献
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In this paper, we define a hierarchy of distribution functions for simultaneous velocity, magnetic, and temperature fields. Some properties of the constructed distribution functions such as reduction, separation, and coincidence are discussed. Equations for the evolution of one- and two-point distribution functions have been derived. Finally, a comparison of the equation for the single-point distribution function in case of zero viscosity, negligible diffusivity, and infinite electrical conductivity is made with first equation of BBGKY hierarchy in the kinetic theory of gases.On study leave from the Department of Mathematics, University of Rajshahi, Bangladesh. 相似文献
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《Planetary and Space Science》1999,47(3-4):469-492
Spectrum analysis of Jupiters great red spot area, rotation, longitude, and latitude, for the period 1963–1967, has been performed. The methods of maximum entropy, power spectrum (Blackman–Tukey approach), Fourier, and autocorrelation have been employed to detect periodicities in the variation of these parameters. The method of successive approximations was applied to the area time-series, and periods of 25, 16, 5 and 3 months and a trend ∼32 months were identified and an analytical expression fit was given, with an accuracy of 78%. Only some periods (6–18 months) describe the main trends of the variation, the shorter (2–5 months) exhibit a stochastic variability, while the longer ones which approach the total record represent a trend. The obtained significant periods and long term trends, common in all methods, are: for latitude; 3.6±0.2, 6.2±0.5, 17.5±3.0 months, a sporadic one of 14.3 months and a trend of 30–35 months, for longitude; 3.9±0.14, 7.3±0.5, 15.6±2 and 19.8±2.5 months, a sporadic one of 5±1 months, and a trend of 30–40 months; for area; 16.6±4.0 and 26±4 months, and sporadic ones 15–17 months and a trend of 32±7 months, and for rotation; 4.8±0.5, 8.3±0.4, 15.2±2.3, 20±3 months, a sporadic one of 5–6 months and a trend of 30–35 months. These periodic terms form a network of periodicities overlapping one upon each other. Various tests of significance and stationarity were applied to examine the reliability and variability of the periodic components.The results of these periodic/quasi-periodic components are discussed in relation to the sunspot numbers, cometary impacts and Jovian atmospheric features. 相似文献
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Abstract— We describe an analytical technique for measurements of Fe, Ni, Co, Mo, Ru, Rh, W, Re, Os, Ir, Pt, and Au in bulk samples of iron meteorites. The technique involves EPMA (Fe, Ni, Co) and LA‐ICP‐MS analyses of individual phases of iron meteorites, followed by calculation of bulk compositions based on the abundances of these phases. We report, for the first time, a consistent set of concentrations of Mo, Ru, Rh, Pd, W, Re, Os, Ir, Pt, and Au in the iron meteorites Arispe, Bennett County, Grant, Cape of Good Hope, Cape York, Carbo, Chinga, Coahuila, Duchesne, Gibeon, Henbury, Mundrabilla, Negrillos, Odessa, Sikhote‐Alin, and Toluca and the Divnoe primitive achondrite. The comparison of our LA‐ICP‐MS data for a number of iron meteorites with high‐precision isotope dilution and INAA data demonstrates the good precision and accuracy of our technique. The narrow ranges of variations of Mo and Pd concentrations within individual groups of iron meteorites suggest that these elements can provide important insights into the evolution of parent bodies of iron meteorites. Under certain assumptions, the Mo concentrations can be used to estimate mass fractions of the metal‐sulfide cores in the parent bodies of iron meteorites. It appears that a range of Pd variations within a group of iron meteorites can serve as a useful indicator of S content in the core of its parent body. 相似文献