Colour-differential interferometry for the observation of extrasolar planets     

M. Vannier  R. G. Petrov  B. Lopez  F. Millour 《Monthly notices of the Royal Astronomical Society》2006,367(2):825-837

We present the high angular resolution technique of colour-differential interferometry for direct detection of extrasolar giant planets (EGPs). The measurement of differential phase with long-baseline ground-based interferometers in the near-infrared could allow the observation of several hot giant extrasolar planets in tight orbit around the nearby stars, and thus yield their low- or mid-resolution spectroscopy, complete orbital data set and mass. Estimates of potentially achievable signal-to-noise ratios are presented for a number of planets already discovered by indirect methods. The limits from the instrumental and atmospheric instability are discussed, and a subsequent observational strategy is proposed.  相似文献   

Low-mass binary-induced outflows from asymptotic giant branch stars     

J. Nordhaus  E. G. Blackman 《Monthly notices of the Royal Astronomical Society》2006,370(4):2004-2012

A significant fraction of planetary nebulae (PNe) and protoplanetary nebulae (PPNe) exhibit aspherical, axisymmetric structures, many of which are highly collimated. The origin of these structures is not entirely understood, however, recent evidence suggests that many observed PNe harbour binary systems, which may play a role in their shaping. In an effort to understand how binaries may produce such asymmetries, we study the effect of low-mass  (<0.3 M_⊙)  companions (planets, brown dwarfs and low-mass main-sequence stars) embedded into the envelope of a  3.0-M_⊙  star during three epochs of its evolution [red giant branch, asymptotic giant branch (AGB), interpulse AGB]. We find that common envelope evolution can lead to three qualitatively different consequences: (i) direct ejection of envelope material resulting in a predominately equatorial outflow, (ii) spin-up of the envelope resulting in the possibility of powering an explosive dynamo-driven jet and (iii) tidal shredding of the companion into a disc which facilitates a disc-driven jet. We study how these features depend on the secondary's mass and discuss observational consequences.  相似文献   

Variations mechanism in entropy of wave height field and its relation with thermodynamic entropy     

郭佩芳侯一筠  钱成春周良民 《中国海洋湖沼学报》2006,24(1):65-68

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An activity catalogue of southern stars     

J. S. Jenkins  H. R. A. Jones  C. G. Tinney  R. P. Butler  C. McCarthy  G. W. Marcy  D. J. Pinfield  B. D. Carter  A. J. Penny 《Monthly notices of the Royal Astronomical Society》2006,372(1):163-173

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An X-ray emission-line spectrum of Nova V382 Velorum 1999     

J.-U. Ness  S. Starrfield  C. Jordan  J. Krautter  J. H. M. M. Schmitt 《Monthly notices of the Royal Astronomical Society》2005,364(3):1015-1024

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Candidate extrasolar planet transits discovered in the Microlensing Observations in Astrophysics-I Galactic bulge data     

F. Abe  I. A. Bond  Y. Furuta  J. B. Hearnshaw  P. M. Kilmartin  Y. Kurata  K. Masuda  Y. Matsubara  Y. Muraki  S. Noda  K. Okajima  N. J. Rattenbury  T. Sako  D. J. Sullivan  T. Sumi  P. Tristram  J. N. Wood  T. Yanagisawa  P. C. M. Yock 《Monthly notices of the Royal Astronomical Society》2005,364(1):325-334

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Behaviour of the SMF method for the numerical integration of satellite orbits     

Pablo Martín  José M. Ferrándiz 《Celestial Mechanics and Dynamical Astronomy》1995,63(1):29-40

The SMF algorithms were recently developed by the authors as a multistep generalization of the ScheifeleG-functions one-step method. Like the last, the proposed codes integrate harmonic oscillations without truncation error and the perturbing parameter appears as a factor of that error when integrating perturbed oscillations. Therefore they seemed to be convenient for the accurate integration of orbital problems after the application of linearizing transformations, such as KS or BF. In this paper we present several numerical experiments concerning the propagation of Earth satellite orbits, that illustrate the performance of the the SMF method. In general, it provides greater accuracy than the usual standard algorithms for similar computational cost.  相似文献   

The dynamical structure of the habitable zone in the HD 38529, HD 168443 and HD 169830 systems     

B. Érdi  R. Dvorak  Zs. Sándor  E. Pilat-Lohinger  B. Funk 《Monthly notices of the Royal Astronomical Society》2004,351(3):1043-1048

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Evaluation and forecasting of daily groundwater outflow in a small chalky watershed     

S. Lallahem  J. Mania 《水文研究》2003,17(8):1561-1577

The purpose of this research is to include expert knowledge as one part of the modelling system and therefore offer the chance to create a productive interaction system between expert, mathematical model (MMO8) and artificial neural networks (ANNs). In the present project, the first objective is to determine some parameters by the MMO8 model, introduced as ANN input parameters to forecast spring outflow. The second objective is first to investigate the effect of temporal information by taking current and past data sets and then to forecast spring outflow. The good results obtained reveal the merit of the ANNs–MMO8 combination, and specifically multilayer perceptron (MLP) models. This methodology, for a network with lower, lag and number hidden layer, consistently produced better performance. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

大地构造和海陆起源的内波假说（Ⅰ）──关于板块学说的若干问题及其思考     

池顺良  锤荣融  杨洪之  骆鸣津 《大地测量与地球动力学》1996,(1)

随着资料的积累，不断发现与板块假说相矛盾的事实：地震层析没有发现地幔对流的证据，却发现大陆克拉通具有４００ｋｍ深的“壳根”；海洋地质调查发现了一系列否定板块假说的重要证据，尤其是大西洋中多处发现古岩石，使海底扩张模型受到严重挑战；跨越扩张脊的一系列测量结果实际上否定了扩张假说。此外，作为学说重要支柱的地磁资料的可靠性受到怀疑，板块消减过程中洋底沉积层堆积被否定，大陆碰撞模式与陆上地质资料的不符，动力机制不明，板块模式不适于解释复杂的大陆地质而难以登陆等事实，已令板块构造理论陷入了深刻的危机之中。根据煤和蒸发岩的地史分布等资料，说明一个海陆相对固定的大地构造模型更符合实际。通过对大地构造假说发展史的分析和研究，并借鉴天文学中太阳系的发现史，认为新假说的建立必须从确凿的地质现象，而非多解性的资料和推断出发。由此提出大地构造和海陆起源的内波假说。  相似文献