55Cancri系中类海王星行星的轨道稳定性

55 Cancri系是已发现的太阳系外众多行星系中的一个,其中心天体类似太阳,周围有4颗巨行星.最内部的行星e是2004年新发现的,质量与海王星类似,但到中心天体的距离却仅为水星到太阳的1/10.这类行星在外太阳系具有典型性.为了探索该类行星的轨道稳定性问题,本文对行星e进行了106年的轨道演化数值模拟.结果表明:除了与相邻行星的2:11共振点外,行星e半长径在小于0.0388AU范围内的轨道都是稳定的.该结果意味着,在类太阳恒星的周围,类海王星质量的行星可以稳定在近距离的轨道上.     

计算机数值方法证明广义相对论的行星运动理论不成立

广义相对论对牛顿引力理论进行修正,在光和行星的运动方程中引入α/r~3的项。由于数学上的困难,目前计算引力场中光和行星轨道运动时都采用近似方法,导致许多重要信息丢失。广义相对论运动方程的轨道极点由一元三次方程确定,有一个或三个实数解。外太空恒星发出的光在太阳系引力场中的轨道是单极点的。本文的严格计算证明,该极点在离太阳中心约5549米的地方。因此外太空恒星发出的光要进入太阳内部被消融,不可能被地球人观察到,地球的夜空应当是黑暗的。然而事实并非如此,广义相对论的光在太阳引力场中的两个实验检验都不成立。精确数值计算结果表明,行星绕日运动轨道存在三个实数极点,第三个极点位于太阳内部施瓦西半径外0.3毫米的地方。行星沿两个相连的三极点类椭圆的轨道运动。因此如果广义相对论正确,行星必将沿小椭圆轨道进入太阳内部被毁灭,这显然与事实不符。恒星在星系中运动时,也存在相同的问题。按照现有广义相对论行星运动方程的近似解,另外一种近似的替代图像是,水星不进入第三极点,但轨道要发生严重的形变。水星绕日一周近日点距离增加9.4万千米,远日点距离减小7.4万千米。水星绕日一周轨道的半正焦弦要改变几千米,这种改变是不对称的和可以累加的,会导致轨道严重变形最终崩溃。由此产生的巨大反差,使广义相对论关于水星近日点进动的计算变得微不足道。然而天文观察并没有发现水星轨道有这样大的改变。本文最后证明,在牛顿引力理论中考虑狭义相对论效应,会导致水星近日点百年16.5″的进动。需要解释的只剩百年26.5″,广义相对论百年43″的计算结果误差达到38.4%。如果在地球参考系的岁差和章动,以及其他行星对水星的引力摄动的计算中也考虑狭义相对论效应,还会引起更大的进动值修正。因此广义相对论对水星近日点进动的计算实际上没有意义。在广义相对论的四个经典实验检验中,与引力场方程有关的三个实验解释都是错的。因此对牛顿引力理论的修正只能按狭义相对论的方式进行,广义相对论对牛顿引力理论的修正不可能是正确的,爱因斯坦弯曲时空引力理论不成立。     

木星平运动共振和Ⅰ型迁移对土星核形成的作用

采用三维N体模拟研究了在太阳星云盘中木星完全形成后土星核的快速形成.除了考虑太阳,木星及行星胚胎间的引力相互作用,还考虑了使行星胚胎发生Ⅰ型迁移和轨道圆化效应的气体盘潮汐作用.模拟表明:木星的平运动共振构型和行星Ⅰ型迁移大大地提高了行星胚胎的碰撞吸积率,同时木星的引力摄动有效地阻止大行星胚胎过快向内迁移而落入太阳中,最终在两百万年的时间内有可能在雪线之外靠近木星3:2平运动共振处吸积形成一颗土星核.     

小行星轨道受木星的平均摄动研究

引进行星系统的基本作用量子η＝λＧＭ＊／ｃ≈９．２８×１０１４ｍ２ｓ－１和行星椭圆轨道的无量纲根数,推导以这种根数表示的小行星轨道受木星的平均摄动函数和三体摄动方程;再由摄动方程计算小行星轨道受木星的平均摄动;最后,给出了几颗特殊小行星轨道受木星的一阶平均摄动数值     

头脑体操

<正>智慧热身八大行星来相聚我们居住的地球,是一颗绕着太阳公转的行星。包括地球在内,一共有八颗行星围绕太阳运转。它们的轨道都近似圆形,并且依次排列,就像这张大图所表示的这样。只是,图中并没有标出每颗行星的名字。你能根据8个方框的描述,把八大行星的名字和它们的位置对应起来吗?海王星:在这里太阳要比地球上看到的暗900倍,非常阴冷,是距离太阳最远的行星。     

太阳系“新家谱”

一、行星成员包括水星、金星、地球、火星、木星、土星、天王星和海王星。定义:围绕太阳运转,自身引力足以克服其刚体力而使天体呈圆球状,并且能够清11除其轨道附近其他物体的天体。二、矮行星成员包括冥王星和谷神星等。定义:与行星同样具有足够的质量,呈圆球状,但不能清除其轨道附近其他物体的天体。三、太阳系小天体定义:围绕太阳运转但不符合行星和矮行星条件的物体。太阳系“新家谱”     

中学物理新大纲中的几个天体问题

一、海王星与冥王星是怎样发现的1. 太阳系家族:在太阳周围,有九个较大的行星(小行星数目较多)围绕着太阳运转。它们是:水星、金星、地球、火星、木星、土星、天王星、海王星和冥王星。如图(一)所示。(最近资料表明土星和天王星之间有可能存在第十颗大行星)。所有这些行星,都沿着同一方向(即所谓顺向)围绕太阳运动,其轨道成椭圆形,极近于圆。其质量大小不一,但所有行星的质量总共只有太     

开普勒第二、第三定律的物理意义

一、由开普勒第二定律可知,行星和太阳之间的联线,在相等的时间内扫过的面积相等。如果以A表示太阳指向行星的位矢所扫过的面积,即 (dA)/(dt)=常数那末,开普勒的该定律的物理意义是什么呢? 我们先看一下dA的表达式。如图,P_1、P_2为行星沿轨道运动时两相邻的位置;行星自     

行星入轨与原子新壳层

在《太阳系行星形成的爆炸波理论》和《新原子壳层和基本粒子分布律》两篇文章中，笔者已经研究了原星球与原太阳碰撞链爆炸形成类地行星和类木行星的过程，以及新原子壳层和基本粒子的分布规律。如果爆炸仅仅发生在核子（如中子、质子）层面，其结果是，原行星还会因太阳的引力被太阳吞食，成为太阳的一部分，不可能形成环绕太阳运行的新行星。本文进一步研究到底是什么力量将所形成的新行星推向其轨道。     

地球和生物演化的爆炸波理论

由一颗原行星撞击原太阳发生链锁大爆炸,所形成的不稳定的小行星序列,按能量相似律运行,随轨道的降低撞向地球发生爆炸,强大的冲击波作用造就了地球和生物演化的节律.     

A closely packed system of low-mass, low-density planets transiting Kepler-11

When an extrasolar planet passes in front of (transits) its star, its radius can be measured from the decrease in starlight and its orbital period from the time between transits. Multiple planets transiting the same star reveal much more: period ratios determine stability and dynamics, mutual gravitational interactions reflect planet masses and orbital shapes, and the fraction of transiting planets observed as multiples has implications for the planarity of planetary systems. But few stars have more than one known transiting planet, and none has more than three. Here we report Kepler spacecraft observations of a single Sun-like star, which we call Kepler-11, that reveal six transiting planets, five with orbital periods between 10 and 47?days and a sixth planet with a longer period. The five inner planets are among the smallest for which mass and size have both been measured, and these measurements imply substantial envelopes of light gases. The degree of coplanarity and proximity of the planetary orbits imply energy dissipation near the end of planet formation.     

Solar eclipses of Phobos and Deimos observed from the surface of Mars

The small martian satellites Phobos and Deimos orbit in synchronous rotation with inclinations of only 0.01 degrees and 0.92 degrees , respectively, relative to the planet's equatorial plane. Thus, an observer at near-equatorial latitudes on Mars could occasionally observe solar eclipses by these satellites (see ref. 1, for example). Because the apparent angular diameter of the satellites is much smaller than that of the Sun, however, such events are more appropriately referred to as transits. Transit data can be used for correcting and refining the orbital ephemerides of the moons. For example, Phobos is known to exhibit a secular acceleration that is caused by tidal dissipation within Mars. Long-term, accurate measurements are needed to refine the magnitude and origin of this dissipation within the martian interior as well as to refine the predicted orbital evolution of both satellites. Here we present observations of six transits of Phobos and Deimos across the solar disk from cameras on Mars aboard the Mars Exploration Rovers Spirit and Opportunity. These are the first direct imaging observations of satellites transiting the Sun from the surface of another planet.     

Infrared radiation from an extrasolar planet

A class of extrasolar giant planets--the so-called 'hot Jupiters' (ref. 1)--orbit within 0.05 au of their primary stars (1 au is the Sun-Earth distance). These planets should be hot and so emit detectable infrared radiation. The planet HD 209458b (refs 3, 4) is an ideal candidate for the detection and characterization of this infrared light because it is eclipsed by the star. This planet has an anomalously large radius (1.35 times that of Jupiter), which may be the result of ongoing tidal dissipation, but this explanation requires a non-zero orbital eccentricity (approximately 0.03; refs 6, 7), maintained by interaction with a hypothetical second planet. Here we report detection of infrared (24 microm) radiation from HD 209458b, by observing the decrement in flux during secondary eclipse, when the planet passes behind the star. The planet's 24-microm flux is 55 +/- 10 microJy (1sigma), with a brightness temperature of 1,130 +/- 150 K, confirming the predicted heating by stellar irradiation. The secondary eclipse occurs at the midpoint between transits of the planet in front of the star (to within +/- 7 min, 1sigma), which means that a dynamically significant orbital eccentricity is unlikely.     

日月食观测在科学研究上的意义

阐述了日月食观测在研究太阳大气结构、太阳活动，寻找近日彗星和水内行星，检验广义相对论理论以及校正历史中年日次序诸多方面的价值．     

封闭式行星传动卷筒的优化设计

以太阳轮及全部行星轮体积和作为目标函数，对封闭式行星传动卷筒传动参数进行了优化设计。优化设计使卷扬装置的综合性能得到提高，并为该装置的系列开发和合理设计提供了有效方法     

The signature of orbital motion from the dayside of the planet τ Boötis b

The giant planet orbiting τ Bo?tis (named τ Bo?tis b) was amongst the first extrasolar planets to be discovered. It is one of the brightest exoplanets and one of the nearest to us, with an orbital period of just a few days. Over the course of more than a decade, measurements of its orbital inclination have been announced and refuted, and have hitherto remained elusive. Here we report the detection of carbon monoxide absorption in the thermal dayside spectrum of τ Bo?tis b. At a spectral resolution of ～100,000, we trace the change in the radial velocity of the planet over a large range in phase, determining an orbital inclination of 44.5°?±?1.5° and a mass 5.95?±?0.28 times that of Jupiter, demonstrating that atmospheric characterization is possible for non-transiting planets. The strong absorption signal points to an atmosphere with a temperature that is decreasing towards higher altitudes, in contrast to the temperature inversion inferred for other highly irradiated planets. This supports the hypothesis that the absorbing compounds believed to cause such atmospheric inversions are destroyed in τ Bo?tis b by the ultraviolet emission from the active host star.     

空间薄膜充气管的太阳辐射压力及外热流分析

本文分析了不同轨道高度以及同一轨道高度不同位置,空间薄膜充气管所受太阳辐射压力及其扭矩大小,以及所受外热流情况.研究发现影响空间薄膜充气管的太阳辐射压力及其产生的扭矩与轨道高度无关,但随轨道位置变化而变化;外热流是轨道高度和位置的函数:随着高度的增加,太阳直接辐射热流不发生变化,但在所有外热流中其数值最大,地球红外辐射热流和地球反照热流则随着轨道的增加而下降,且后者下降的速度更快.     

Little or no solar wind enters Venus' atmosphere at solar minimum

Venus has no significant internal magnetic field, which allows the solar wind to interact directly with its atmosphere. A field is induced in this interaction, which partially shields the atmosphere, but we have no knowledge of how effective that shield is at solar minimum. (Our current knowledge of the solar wind interaction with Venus is derived from measurements at solar maximum.) The bow shock is close to the planet, meaning that it is possible that some solar wind could be absorbed by the atmosphere and contribute to the evolution of the atmosphere. Here we report magnetic field measurements from the Venus Express spacecraft in the plasma environment surrounding Venus. The bow shock under low solar activity conditions seems to be in the position that would be expected from a complete deflection by a magnetized ionosphere. Therefore little solar wind enters the Venus ionosphere even at solar minimum.     

冥王星的奇特轨道性质

被称为第九大行星的冥王星具有与其它八大行星不同的高倾角、高偏心率的共振锁定轨道，而在新发现的外太阳系的Kuiper带中许多天体却具有与之相似的轨道性质，因此冥王星更像是一颗Kuiper带天体而不是大行星．