夏夜星空与银河系的发现

夏夜银河贯南北,天鹅河中展翅游。织女河西拨琴弦,牛郎偕子岸边候。南天人马对天蝎,南斗心宿有看头。巨蛇蛇夫并武仙,回首西北见北斗。     

船用星敏感器星点质心精确提取方法

从星空图像中提取星点质心是星敏感器工作的重要基础,针对船用星敏感器所获取的星空图像噪声情况复杂的特点,提出一种基于重心法的星点质心精确提取方法。通过块扫描的阈值分割和星象连续性的噪点剔除,引入灰度信息参考的星象提取以及重心法质心坐标计算等步骤,从星空图像中提取星点质心。对于30幅海上实拍星图实验,该方法能够100%提取出至少10颗星点,质心坐标提取精度达到1/20像素,并且可以实现对视频图像的实时处理,满足船用星敏感器的应用需求。     

走近天文之二 理解星座的真面目

<正>1引言星座可以说是天文学的起点,古代天文学家用星座来跟踪日月星辰的运行规律,告诉我们时间历法。在这个过程里,古人还编织了非常生动有趣的星座故事,如今通过这些故事,我们可以理解究竟星座是怎么回事儿。通过破解占星术的秘密,我们还可以理解古人对于天文现象的疑问,思索我们和宇宙之间的联系。"生日星座"(星宫)是一种时尚文化,在大多数解读中误解了它和天上星座之间的关系,笔者通过溯     

Constraints on Deceleration Parameter of a 5D Bounce Cosmological Model from Recent Cosmic Observations

We study the constraint on deceleration parameter q from the recent SNela Gold dataset and observational Hubble data by using a model-independent deceleration parameter q（z） = 1/2 - a/（1 ＋ z）^b under the flve-dimensional bounce cosmological model. For the cases of SNeIa Gold dataset, Hubble data, and their combination, the present results show that the constraints on transition redshift ZT are 0.35-0.07^＋0.14,0.68-0.58^＋1.47,and 0.55-0.09^＋0.18 with 1σ errors,respectively.     

暗能量:观测证据和理论研究

自1998年发现宇宙的加速膨胀以来,大量的天文观测显示宇宙中存在压强为负的暗能量成分.暗能量已经成为目前宇宙学和理论物理的最重要的研究课题之一.文章介绍了暗能量存在的天文观测证据和理论研究现状与展望.     

透镜在生活中的应用

透镜在生产、生活中很常见,从天文观测用的大型望远镜到我们身边的放大镜、眼镜、照相机、显微镜等。透镜大致可以分为凸透镜和凹透镜两种。凸透镜对光线有会聚作用;凹透镜对光线有发散作用。应用这一原理,人们发明了放大镜、眼镜、照相机、望远镜、显微镜、幻灯机、投影仪、放映机等光学仪器。透镜给我们的生活带来了方便。同时还促进了人类对宇宙天体及微观世界的认识,更促进了人类的文明进步和社会发展。     

探索我们的宇宙 发展相对性原理——国际天文年暨爱因斯坦诞辰130周年纪

一、引言今年是国际天文年,主题为“探索我们的宇宙”。以纪念400年前伽利略开始用望远镜进行天文观测所开启的人类对宇宙的科学探索。今年又恰逢爱因斯坦这位上个世纪最伟大的科学家诞辰130周年。在国际天文年纪念爱因斯坦诞辰130周年,具有特殊的意义。     

正视我国学者在天象上的发现权

 我们伟大的祖国历史悠久、文化发达,古代天文学的发展在世界文明史上占有重要地位,有很多宝贵的观测资料,创造发明了不少天文仪器。但也有一些本应属于我国学者的天象或其原理的发现权,由于未能及时发掘出来并公诸于世,多年来一直让西方学者独占鳌头。现试举3例如下:一、甘德最早发现木星最大的卫星木卫三我国研究自然科学史的专家席泽宗院士考证出我国战国时期的天文学家甘德早在意大利科学家伽     

一个了解宇宙的新窗口——分子天体物理学介绍

 现代科学的显著特点之一是它的综合性和整体性,即各个学科之间的交互影响.分子天体物理学的建立和发展是一个很好的例子.在它的发展过程中,物理学和化学的基础研究,射电天文学和空间天文学的最新技术成就与天体物理学和天体化学密切配合,相互推动.在短短的二十多年中形成了一门生气勃勃的新学科.它为天文学提供了一个了解宇宙的新窗口,有力地推动了恒星演化的极早期阶段和晚期阶段的研究.     

Nuclear Forces and Neutron Stars

Earlier work on nuclear forces is applied to astudy of cooled massive neutron stars. Nuclear forcesinside these stars cannot be neglected and theirinfluence on neutron star states is considered. One important property of nuclear forces is theirability to be repulsive, which results in the phenomenonof nuclear saturation. It is shown that this propertycan provide the balance of gravitational and nuclear forces in cooled massive neutronstars.     

Oscillations and Collapses of Proto--Neutron Stars

We examine the oscillation and collapse of a relativistic star, e.g., a proto-neutron star, with an equation of state （EOS） which is Mowly changing as driven by, e.g., losing of thermal energy through radiations. We find that the frequency of the fundamental mode of oscillation （radial） will gradually increase then abruptly drop to zero when the star gets close to the point of instability. We also find that for a wide range of configurations on the unstable branch of equilibrium configurations, the collapse is dominated by one unstable mode.     

Apparent and real roughness

Some works have studied the light scattering from a rough surface immersed in a liquid, where the light scattered from the immersed rough surface was assumed to be equivalent to that scattered from a fictitious rough surface with a different texture. This work deals with this kind of problems analyzing the light scattered by a reflecting strong scatterer and the light scattered by a rough surface immersed in a transparent liquid. The general Kirchhoff solution for scattering from a rough surface has been used.It is shown that under certain conditions, the mean scattered intensity (MSI) from a surface immersed in a liquid can be quasi-indistinguishable from that scattered from a non-immersed surface with an “equivalent texture”. An expression relating the equivalent texture and the immersed surface texture was obtained.The results of this work allow to evaluate the characteristics of any surface immersed in a liquid with a known refractive index.     

Gravitational Lensing of Fermion Stars

We discuss the fermion stars, the self-gravitating systems of Fermi gases, as possible gravitational lenses. It is supposed that the fermions interact with themselves and other particles only by gravity, so they are the candidates of dark matter. We calculate Einstein deflection angles, study the image configurations, and calculate the magnification factors for a number of fermion stars that range from strong relativistic configurations to nonrelativistic ones. We find that typically there are three images, one Einstein ring and one radial critical curve for both cases. Two of the images are within the Einstein ring, and the other is outside, which may be very far. All these lensing characteristics can help to identify fermion stars as potential lensing objects, thus might give direct evidence that dark fermion stars exist in the universe.     

On Existence of Mini-Boson Stars

We prove the existence of a countable family of globally regular solutions of spherically symmetric Einstein–Klein–Gordon equations. These solutions, known as mini-boson stars, were discovered numerically many years ago. Received: 14 February 2000 / Accepted: 26 June 2000     

贫金属星的表面丰度与慢中子俘获过程

在不依赖于特定恒星模型的前提下,采用参数化热脉冲模型,对三颗铅星的表面丰度进行了拟合计算.结果表明,无论是否考虑分叉道的影响,结果均能很好地重现观测数据.另外,铅星与非铅星的模型参量对比显示,铅星的平均中子辐照量远大于非铅星,而其挖掘程度明显小于非铅星.这说明尽管参数化热脉冲模型过于简单,但对约束恒星模型仍具有重要意义.