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中学生英语 2006年第Z3期 56-57页

作者：晓梅

Searching for exoplanets with HEPS:*** probability of Earth-like planets in multiple systems

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Research in Astronomy and Astrophysics 2019年第1期19卷 35-46页

作者： Zhou-Yi Yu Hui-Gen Liu Ji-Lin Zhou Dong-Hong Wu Ming Yang Songhu Wang Hui Zhang Zi Zhu Jia-Cheng Liu School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics in Ministry of EducationNanjing University Department of Astronomy Yale University

The astrometry method has great advantages in searching for exoplanets in the habitable zone around solar-like stars. However, the presence of multiple planets may cause a problem with degeneracy when trying to compute accurate planet parameters from observation data and reduce detectability. The degeneracy problem is extremely critical, especially in a space mission which has limited observation time and cadence. In this series of papers, we study the detectability of habitable Earth-mass planets in different types of multi-planet systems, aiming to find the most favorable targets for the potential space mission–Habitable ExoPlanet Survey(HEPS). In the first paper, we present an algorithm to find planets in the habitable zone around solar-like stars using astrometry. We find the detectability can be well described by planets' signal-to-noise ratio(SNR) and a defined parameter S = M2/(T1-T2)2, where M2 and T2are the mass and period of the second planet, respectively. T1 is the period of the planet in the habitable zone. The parameter S represents the influence of planetary architectures. We fit the detectability as a function of both the SNR of the planet in the habitable zone and the parameter S. An Earth-like planet in a habitable zone is harder to detect(with detectability PHP< 80%) in a system with a hot Jupiter or warm Jupiter(within2 AU), in which the parameter S is large. These results can be used in target selections and to determine the priority of target stars for HEPS, especially when we select and rank nearby planet hosts with a single planet.

关键词： astrometry stars:planetary systems planets and satellites:detection methods:numerical

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Stagnant lid tectonics:Perspectives from silicate planets,dwarf planets, large moons,and large asteroids

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Geoscience Frontiers 2018年第1期9卷 103-119页

作者： Robert J.Stern Taras Gerya Paul J.Tackley Geosciences Department University of Texas at Dallas Department of Earth Sciences ETH-Zurich

To better understand Earth's present tectonic style-plate tectonics—and how it may have evolved from single plate(stagnant lid) tectonics, it is instructive to consider how common it is among similar bodies in the Solar System. Plate tectonics is a style of convection for an active planetoid where lid fragment(plate) motions reflect sinking of dense lithosphere in subduction zones, causing upwelling of asthenosphere at divergent plate boundaries and accompanied by focused upwellings, or mantle plumes;any other tectonic style is usefully called "stagnant lid" or "fragmented lid". In 2015 humanity completed a 50+ year effort to survey the 30 largest planets, asteroids, satellites, and inner Kuiper Belt objects,which we informally call "planetoids" and use especially images of these bodies to infer their tectonic activity. The four largest planetoids are enveloped in gas and ice(Jupiter, Saturn, Uranus, and Neptune)and are not considered. The other 26 planetoids range in mass over 5 orders of magnitude and in diameter over 2 orders of magnitude, from massive Earth down to tiny Proteus; these bodies also range widely in density, from 1000 to 5500 kg/m^3. A gap separates 8 silicate planetoids with ρ = 3000 kg/m^3 or greater from 20 icy planetoids(including the gaseous and icy giant planets) with ρ = 2200 kg/m^3 or less. We define the "Tectonic Activity Index"(TAI), scoring each body from 0 to 3 based on evidence for recent volcanism, deformation, and resurfacing(inferred from impact crater density). Nine planetoids with TAI = 2 or greater are interpreted to be tectonically and convectively active whereas 17 with TAI <2 are inferred to be tectonically dead. We further infer that active planetoids have lithospheres or icy shells overlying asthenosphere or water/weak ice. TAI of silicate(rocky) planetoids positively correlates with their inferred Rayleigh number. We conclude that some type of stagnant lid tectonics is the dominant mode of heat loss and that plate tectonics

关键词： Stagnant lid Solar system Plate tectonics planets Moons

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WHY CAN THE MAJOR planets HAVE THEIR SATELLITES MOVING IN DIRECT AND RETROGRADE ORBITS AS WELL?

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Applied Mathematics and Mechanics(English Edition) 1991年第4期12卷 339-343页

作者：汪家訸 Zhejiang University Hangzhou

Now we use the Jacobian integral of circular restricted three-body problem to establish a testing function of the stability of satellites. This method of criterion may be applied to the stability problem of satellites when the six elements of the instantaneous orbit of the satellite with respect to its parent planet are known. By means of an electronic computer, we can find the stable region of a satellite with a quasi-circular orbit. The boundary surface of this region is a nearly oblate ellipsoid. The volume of this enclosed space is much smaller than that of binding by Hill surface and that of 'sphere of action'. As the expressions of relative kinetic energy of a satellite with respect to its parent planet have the same form for the direct as well as the retrograde orbits, they can coexist in the same region at the same time.

关键词： Computers Applications Mathematical Models Moon planets Stability

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Phase-Space Areas of the Body Motion in the Solar System Deduced from the Bohr-Sommerfeld Atomic Theory and Approximate Invariance of Their Ratios for the Pairs of planets and Satellites

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Journal of Modern Physics 2012年第9期3卷 1142-1151页

作者： Stanislaw Olszewski Tadeusz Kwiatkowski Institute of Physical Chemistry Polish Academy of Science Warsaw Poland

Energy-time and momentum-position phase spaces defined by the electron orbits in the hydrogen-like atom exhibit special properties of equivalence. It is demonstrated that equivalence of the same kind can be obtained for the phase-space areas defined by the orbit pairs of planets, or satellites, which compose the solar system. In the choice of the examined areas it is useful to be guided by the Bohr-Sommerfeld atomic theory.

关键词： Ratios of the Phase-Space Areas and Their Invariance planets and Satellites Bohr-Sommerfeld Atomic Theory

Gravitational transformation of gaseous clouds: The formation of spiral galaxies and disk planets

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Natural Science 2014年第4期6卷 151-170页

作者： Andrei Pavlov Orvokkikatu 8 Naantali Finland

Gravitation is one of the central forces playing an important role in formation of natural systems like galaxies and planets. Gravitational forces between particles of a gaseous cloud transform the cloud into spherical shells and disks of higher density during gravitational contraction. The density can reach that of a solid body. The theoretical model was tested to model the formation of a spiral galaxy and Saturn. The formations of a spiral galaxy and Saturn and its disk are simulated using a novel N-body self-gravitational model. It is demonstrated that the formation of the spirals of the galaxy and disk of the planet is the result of gravitational contraction of a slowly rotated particle cloud that has a shape of slightly deformed sphere for Saturn and ellipsoid for the spiral galaxy. For Saturn, the sphere was flattened by a coefficient of 0.8 along the axis of rotation. During the gravitational contraction, the major part of the cloud transformed into a planet and a minor part transformed into a disk. The thin structured disk is a result of the electromagnetic interaction in which the magnetic forces acting on charged particles of the cloud originate from the core of the planet.

关键词： Gravitation planets Saturn’s Rings Computer Simulation Planet’s Interior Structure Formation of Galaxies Spiral Galaxies N-Body Simulations

Dynamic Problems of the planets and Asteroids, and Their Discussion

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International Journal of Astronomy and Astrophysics 2012年第3期2卷 129-155页

作者： Joseph J. Smulsky Yaroslav J. Smulsky Institute of the Earth’s Cryosphere Siberian Branch of Russian Academy of Sciences Tyumen Russia Institute of Thermophysics of Russian Academy of Sciences Siberian Branch Novosibirsk Russia

The problems of dynamics of celestial bodies are considered which in the literature are explained by instability and randomness of movements. The dynamics of planets orbits on an interval 100 million years was investigated by new numerical method and its stability is established. The same method is used for computing movements of two asteroids Apophis and 1950DA. The evolution of their movement on an interval of 1000 is investigated. The moments of their closest passages at the Earth are defined. The different ways of transformation of asteroids trajectories into orbits of the Earth’s satellites are considered. The problems of interest are discussed from the different points of view.

关键词： Dynamics planets Asteroids Satellites Stability Discussion

Edward Burne-Jones＇s The planets.＂ Musical Spheres and Visions of a Benevolent Cosmos

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Journal of Literature and Art Studies 2017年第7期7卷 812-868页

作者： Liana De Girolami Cheney SIELAE Universidad de Corufia Corufia Spain

Edward Burne-Jones （1833-1898）, a pre-Raphaelite painter, was fascinated with astronomy, as noted in his memorials and accounts. In 1879, he executed cartoon drawings for a cycle on nine planets for the artisans of the William Morris Firm, who would transform them into stained-glass panels. The commission was for the decoration of Woodlands, the Victorian mansion of Baron Angus Holden （1833-1912）, a major of Bradford. Presently, seven of the cartoons--The Moon （Luna）, Earth （Terra）, Sol （Apollo）, Venus, Jupiter, Saturn, and Evening Star--are in the Torre Abbey Museum in Torquay, UK, while the cartoon for Mars is part of the collection of drawings at the Birmingham Museum and Art Gallery, UK, and the cartoon for Morning Star is located at Lady Margaret Hall in Oxford, UK. In the creation of the planets cycle, Burne-Jones was inspired by cultural events of the time such as British scientific astronomical discoveries and British and Italian humanistic sources in literature and visual arts portraying astronomy. This essay art historically and iconographically examines the nine planets as celestial and terrestrial formations and astral spheres of good omen. It is composed of three sections. The first section discusses the history of the artistic commission; the second analyzes the stylistic and iconographical aspects of the planets cycle; and the third section explains some of Burne-Jones＇s cultural sources for the planets cycle as manifestations of seasonal transformations, heavenly and terrestrial realms, musical spheres, and visions of a benevolent cosmos.

关键词： British astronomy Italian astrology celestial cosmos planets musical spheres seasons Victorianhomes Edward Bume-Jones

A Novel Explanation of the Origin of the Magnetic Field of Stars and planets

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Open Journal of Applied Sciences 2023年第8期13卷 1289-1300页

作者： Elie W’ishe Sorongane Physics Department University of Kinshasa Kinshasa Democratic Republic of the Congo

Today, the origin of the magnetic field of stars and planets is explained by the dynamo effect. Since Cowling’s anti-dynamo theorem has forbidden a purely axisymmetric dynamo, scientists are all convinced today that the fluid flow in the core of a star cannot be laminar, so it is turbulent. However, we will see in this study that the configuration in which the conductive fluid contained in the core of a star is in rapid rotation around an axis of symmetry is the one that best explains the origin of the magnetic field of stars and planets. It also explains why certain types of stars have very intense magnetic fields. Indeed, we will show here that the magnetic field of stars and planets is created by the electric current generated by the rotational movement of charged fluid particles as in an electromagnet. The lines of this magnetic field are channelled by the solid paramagnetic seed which plays the role of magnetic core in the cores of planets and stars. The seed is composed mainly of Iron and Nickel on the planets and of solid helium-3 in the stars. In this work, we will use this model of rapidly rotating fluids to introduce a new way to ionize a neutral gas and maintain it in a plasma state for indefinitely large time scales, to present a new technique for generating very intense magnetic fields, to establish a new magnetic nucleation process and to propose a new type of nuclear fusion reactor in which the plasma is perpetually rapidly rotating.

关键词： Magnetic Field Stars planets Electromagnet Fluid Rotation Plasma

Is Highly Organized Life Present on Recently Discovered planets in Our Galaxy?

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Atmospheric and Climate Sciences 2017年第3期7卷 298-300页

作者： Wennan Long George V. Chilingar Petroleum Engineering Program Mork Family Department University of Southern California Los Angeles CA USA

The question arises whether organized life (as it exists on the Earth) exists on newly-found planets or not, such as Kepler 186f, in our Galaxy. The Earth’s evolution is defined by three critical factors: 1) Solar luminosity, 2) The distance between the Earth and Sun and 3) The Earth’s mass and chemical compositions. All these variables were favorable for the emergence and development of highly-organized life on our Earth.

关键词： Origin of Life Uniqueness of the Earth Kepler 186f Newly-Found planets Earth’s Evolution