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121.
对金斯定则的几点认识   总被引:1,自引:0,他引:1  
高崇伊 《天文学报》2002,43(4):366-374
用物理学基本定律可导出金斯经验定则,它似应称为金斯定则,该定则的速度、高度或能量等表述完全等效,可随意选用,用能量观点更容易解释此定则,满足金斯定则只是给定的粒子成为具有稠密大气的行星或卫星的主要大气成分的必要条件,该定则的适应范围可用方程或其图像表示,也能用诺模图确定,它适用于太阳系内的行星,卫星,小行星,流星体和像柯伊伯带天体与半人马族星这样的外太阳系天体,此定则现在仍有普遍的现实意义。  相似文献   
122.
This paper discusses the main results of a search of outer Trojans on ESO/ESA ASTROVIRTEL images, and the usefulness and the limitations of such an archive for the discovery and dynamical classification of minor bodies. The work was performed in the frame of a program having the aim to detect bodies orbiting around the Lagrangian points of the outer planets. A large number of images taken from 1999 to 2001 with the wide field imager (WFI) camera of the 2.2 m telescope of ESO at La Silla for entirely different scientific reasons, but happening to be in the wanted Lagrangian positions, was retrieved with a dedicated search engine. The moving objects present on these images were detected and examined with specific software tools that permitted one to find out about 1500 minor bodies (mostly previously unknown). More than 5000 positions were sent to the Minor Planet Center, and the search was given the designation I03. The total sky area covered by I03 is of approximately 50 square degrees, and in some areas the limiting magnitudes were fainter than the 24th in the R band. A preliminary classification of the kinematics of the I03 discoveries (using a dedicated code, named AMIGO apparent motion interpretation of generic orbits) has produced several Trojan candidates of Jupiter and of the outer planets. Furthermore, pre-discovery positions have been provided for one NEO, three Jupiter Trojans and three TNOs.  相似文献   
123.
The island of Ischia belongs to the active volcanic area of Naples. It is formed from Quaternary volcanic rocks and exhibits intense hydrothermal activity, which is manifested through numerous springs, fumaroles and sporadic geysers. The content of minor and trace elements in groundwater has been analyzed, including some elements that are considered toxic for humans. Mean concentrations of As, B, Fe, Mn, Sb, and Se in samples from 43 aquifer points exceed the WHO recommended values and the limits set by European and Italian legislation (98/83/CE and DM 471, respectively). In general, the spatial distribution of the elements follows a common pattern: it is governed by a marked structural control, which favors hydrochemical processes that liberate the elements into the water.  相似文献   
124.
For the general and restricted elliptic planetary spatial three-bodyproblems under the oblateness of the central body and at both third-orderorbital and secondary resonances, the analytical solutions are obtained bythe use of the Weierstrass functions with an accuracy of the fourth-degreeterms in the eccentricities and inclinations. The behaviour of solutions isstudied on the phase plane.  相似文献   
125.
The Eddington mission was given full approval by the European Space Agencyon the 23rd May 2002, as part of the new `Cosmic Vision' Science programme, with launch scheduled for 2007/8. Its twin scienceobjectives are asteroseismology and planet finding.In its current design it consists of 4 × 60 cm folded Schmidt telescopes, eachwith 6° × 6° field of view and its own CCD array camera.The current observing plan is to spend 2 years primarily devoted to asteroseismologywith 1–3 months on different target fields monitoring up to 50,000 stars per field,and 3 years continuously on asingle target field monitoring upwards of 100,000 stars as required for planetsearching. The asteroseismic goal is to be able to detect oscillationsfrequencies with a precision 0.1–0.3 Hz.  相似文献   
126.
The general evolution of planets in the Solar System is discussed with a focus on the structure and history of Venus compared with the Earth. The history of the planets of the terrestrial group has been similar and included at least six correlated stages. Many common features the terrestrial planets shared in their early and late evolution have been due to their common origin from the protoplanetary gas-and-dust nebula and plume magmatism widespread on all the planets of the terrestrial group. The characteristic features of the structure and evolution of Venus are most brightly manifested in the specific composition of its atmosphere and of plume magmatism. Venus, with its surface as hot as 450 °C and the near-surface pressure of 92-93 bars, has a hot and dense atmosphere 93 times that of the Earth in mass. Most of its atmospheric mass (99%) belongs to the 65-km thick troposphere consisting of CO2 (96.5%) and N2 (3.5%). The upper troposphere includes a 25-30 km thick cloud layer composed mainly of sulfuric acid droplets, water vapor, and SO2. At a height of 49.58 km, the clouds approach the conditions of the terrestrial surface and might be hospitable to bacterial life. Volcanism, the most active and widespread process of Venusian geology, maintains continuous SO2 emission. There are diverse volcanic edifices on Venus, which are most often large and are similar to the Earth’s plume-related volcanoes. The evolution before 1 Ga, as well as the share and the role of alkaline rocks and carbonatites among its volcanics, are among the most debatable issues about Venus. Being located closer to the Sun, Venus cooled down more slowly and less intensely than the Earth after the primary accretion. In the Proterozoic, it began heating and reached its present state at ~ 1 or 2 Ga. In the future, as the Sun becomes a red giant, the Earth is predicted to begin heating up in 500-600 Myr to reach the temperature of present Venus in about 1.5 Gyr.  相似文献   
127.
太阳系探测的进展与比较行星学的主要科学问题   总被引:1,自引:0,他引:1  
回顾了太阳系的探测历程,综合分析了太阳系探测的发展趋势。未来的太阳系探测将以月球与火星探测为主线,适度开展太阳系其他行星及其卫星、小行星和彗星的考察性探测。21世纪将是全面探测太阳系并为人类社会长期可持续发展服务的新时代。随着太阳系探测的进展,通过系统比较地球与类地行星的大气层与水体的形成演化过程、地形地貌与地质构造特征、岩石类型、热历史与内部结构等方面的共性与特性研究,表明行星的质量大小和行星与太阳的距离的相互耦合,制约了行星的形成和演化的复杂过程。比较行星学已成为指导太阳系探测的科学理论体系。  相似文献   
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