晚型恒星中的类太阳活动（Ⅰ）：恒星黑子,活动周和磁场     

翟迪生 《天文学进展》1990,8(3):189-197

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A Model for Contact Binary Systems     

Han-Feng Song Run-Qian Huang Shao-Lan Bi 《中国天文和天体物理学报》2007,7(4):539-550

A model for contact binary systems is presented, which incorporates the following special features: a) The energy exchange between the components is based on the understand-ing that the energy exchange is due to the release of potential, kinetic and thermal energies of the exchanged mass. b) A special form of mass and angular momentum loss occurring in contact binaries is losses via the outer Lagrangian point. c) The effects of spin, orbital rota-tion and tidal action on the stellar structure as well as the effect of meridian circulation on the mixing of the chemical elements are considered. d) The model is valid not only for low-mass contact binaries but also for high-mass contact binaries. For illustration, we used the model to trace the evolution of a massive binary system consisting of one 12M and one 5M star. The result shows that the start and end of the contact stage fall within the semi-detached phase during which the primary continually transfers mass to the secondary. The time span of the contact stage is short and the mass transfer rate is very large. Therefore, the contact stage can be regarded as a special part of the semi-detached phase with a large mass transfer rate. Both mass loss through the outer Lagrangian point and oscillation between contact and semi-contact states can occur during the contact phase, and the effective temperatures of the primary and the secondary are almost equal.  相似文献   

天体物理环境中的硅酸盐尘粒   总被引：1，自引：0，他引：1  

李墨萍  赵刚  李爱根 《天文学进展》2007,25(2):132-146

硅酸盐尘粒是宇宙尘埃的主要成分之一,它广泛存在于许多天体物理环境中,其特性随环境而变化。由于近年来观测数据的不断增加和红外光谱质量的逐步提高,宇宙空间中的硅酸盐尘粒正受到越来越多的关注．该文详细地介绍了在各种天体环境(星际空间、演化晚期恒星的星周尘埃包层、绕年轻恒星和主序星的星周尘埃盘、彗星的彗发和行星际空间)中的硅酸盐尘粒的观测特征,并分别对其物理和化学性质进行了综合比较．观测已经证实在星际尘埃演化的前身(演化晚期恒星的星周尘埃包层)和其遗迹(彗星)均有可观数量的结晶硅酸盐存在。但是至今还没有在其中间态(弥散星际介质)找到结晶硅酸盐存在的证据。这一尚未解决的难题突出了结晶态硅酸盐在天体物理研究中的重要意义。  相似文献   

Mkn501长期光变性质     

杨江河  樊军辉  刘怡  王永祥  杨如曙 《天文学报》2007,48(4):407-417

在R和I波段对Mkn 501进行了测光观测,并结合历史文献得到Mkn 501在近30年间的光学、红外和射电等多个波段的光变曲线;讨论了光变与色指数之间的关系,发现色指数(B—V)与(B—R)之间有强相关,相关系数r=0.73.利用DCF方法分析了多波段光变的相关性,发现B波段与4.8GHz和红外波段的光变存在一定的正相关,利用CLEANest方法对B波段的光变曲线进行频谱分析,结果表明Mkn 501的光变曲线存在2个可能的周期,即(10.06±0.04)年和(21.60±0.17)年.  相似文献   

The Origin and Acceleration of ~3He and Heavy Ions in the 2000 July 14 Event     

Gui-Ping Wu  Guang-Li Huang  Yu-Hua Tang  Yu Dai Department of Physics  Southeast University  Nanjing  Purple Mountain Observatory  Chinese Academy of Sciences  Nanjing Department of Astronomy  Nanjing University  Nanjing 《中国天文和天体物理学报》2007,7(1):141-147

1INTRODUCTIONEnrichment of3He and heavy ions(i.e.,Ne,Mg,Si and Fe),characteristic of impulsive?ares,have beenstudied for more than three decades.It is found that they are generally associated with nonthermal energeticelectron-rich events(Reames et al.1988;Reames1999and references therein;Ho et al.2001;Wang et al.2006)and are related to the peculiar ratio of charge to mass(Mazur et al.1996;Reames1999).Althoughthe abundance of3He ions is not correlated with the abundance of heavy ions,s…  相似文献   

Eclipses and Occultations of Galilean Satellites Observed at Yunnan Observatory in 2003     

Benot Noyelles 《中国天文和天体物理学报》2007,7(2):317-324

We describe and analyze observations of mutual events of Galilean satellites made at the Yunnan Observatory in February 2003 from CCD imaging for the first time in China. Astrometric positions were deduced from these photometric observations by modelling the relative motion and the photometry of the involved satellites during each event.  相似文献   

Simulation Study on High Energy Cosmic Electron Detection by Shower Image     

S.Torii  K.Kasahara  T.Tamura  K.Yoshida 《中国天文和天体物理学报》2007,7(6):839-844

Many projects have recently been carried out and proposed for observing high energy electrons since it is realized that cosmic ray electrons are very important when study-ing the dark matter particles and the acceleration mechanism of cosmic rays. An imaging calorimeter,BETS (Balloon-borne Electron Telescope with Scintillator fiber),has been de-veloped for this purpose. Using pattern analysis of the shower development,the electrons can be selected from those primary cosmic ray proton events with flux heights one-tenth that of the electrons. The Monte-Carlo simulation is indispensable for the instrument design,the sig-nal trigger and the data analysis. We present different shower simulation codes and compare the simulation results with the beam test and the flight data of BETS. We conclude that the code FLUKA2002 gives the most consistent results with the experimental data.  相似文献   

1：500DLG数据的质量控制与质量评价   总被引：1，自引：0，他引：1  

曾敬文 《北京测绘》2009,(3):66-68

DLG数据是城市地形要素的主要表达形式，如何对DLG数据的采集过程进行质量控制、质量检查，如何对DLG数据进行客观的质量评价，是值得探讨和研究的问题。本文针对1：500DLG数据生产的各个环节，全面介绍了其质量控制、质量检查、质量验收、质量评定的内容和方法。  相似文献   

Cross-Correlation Detection of Point Sources in the WMAP First Year Data     

Jian-Yin Nie  Shuang-Nan Zhang  Department of Physics  Center for Astrophysics  Tsinghua University  Beijing  Key Laboratory of Particle Astrophysics  Institute of High Energy Physics  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2007,7(2):199-208

We apply a Cross-Correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We find that the CC method is a pow- erful tool to examine the WMAP foreground residuals which can be further cleaned accord- ingly. Evident foreground signals are found in the WMAP foreground cleaned maps and the Tegmark cleaned map. In this process 101 point sources are detected, and 26 of them are new sources additional to the originally listed WMAP 208 sources. We estimate the ?ux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.  相似文献   

A New Feature Vector Using Selected Line Spectra for Pulsar Signal Bispectrum Characteristic Analysis and Recognition   总被引：1，自引：0，他引：1  

Zhen-Hua Xie Lu-Ping XU Guang-Ren Ni Yan Wang 《中国天文和天体物理学报》2007,7(4):565-571

Average pulse profiles of pulsar signals are analyzed using the bispectrum tech-nique. The result shows that there are nonlinear phase couplings between the two frequency axes of the bispectrum charts, which indicate nonlinear factors in the generation and prop-agation of pulsar signals. Bispectra can be used as feature vectors of pulsar signals because of their being translation invariant. A one-dimension selected line spectrum algorithm for ex-tracting pulsar signal characteristic is proposed. Compared with selected bispectra, the pro-posed selected line spectra have the maximum interclass separability measurements from the point of view of the whole one-dimension feature vector. Recognition experiments on several pulsar signals received at several frequency bands are carried out. The result shows that the selected line spectrum algorithm is suitable for extracting pulsar signal characteristics and has a good classification performance.  相似文献