共查询到20条相似文献，搜索用时 31 毫秒
1.
The number of reference points for the fixing of a selenodetic reference frame in the Moon’s body is estimated. It is shown
that, for this purpose, from 40 to 100 reference points are sufficient. Precision of the selenodetic coordinate transformations
from one system to another is also analysed. 相似文献
2.
A new coordinate system – heliomagnetic reference frame – has been proposed in which the great circle passes through the solar
pole and the north pole of the magnetic dipole is considered as the central meridian. It is shown that, in the new coordinate
system, the active longitudes are defined much more clearly, are more stable in time, and are interlaced every 11 years. 相似文献
3.
Toshio Fukushima 《Celestial Mechanics and Dynamical Astronomy》1988,44(1-2):61-75
The Fermi coordinate system (or the non-rotating proper reference frame) is studied within the framework of the post-Newtonian approximation of general relativity. First its general functional form is found to consist of three parts; (1) the motion of the space origin of the Fermi coordinate system relative to the background one, (2) the Fermi-Walker tetrad transported along the world line of the space origin, and (3) the spacelike geodesic starting from the space origin. Next, the post-Newtonian expressions of the latter two are obtained under the condition that the first is given. Then the full coordinate transformation formula connecting the Fermi coordinate system to the background one is derived explicitly. The effectiveness of the Fermi coordinate system is discussed and the effective region is found to be a cylinder with the radius of about 0.5 kpc for the Fermi coordinate system comoving with the Earth. The mathematical way to derive the generalized Fermi coordinate system which Ashby and Bertotti defined is also shown. 相似文献
4.
X. Ribeyre L. Hallo V. T. Tikhonchuk S. Bouquet J. Sanz 《Astrophysics and Space Science》2007,307(1-3):169-172
The Rayleigh-Taylor instability (RTI) plays an important role in the dynamics of several astronomical objects, in particular,
in the supernovae (SN) evolution. In the present paper we examine the dynamics of a shell (representing a type II SN remnant)
blown-up by a wind emitted by a central pulsar. The shell is accelerated by the pulsar wind and its inner surface experiences
the RTI. We develop an analytical approach by using a specific transformation into the coordinate frame co-moving with the
SN ejecta. We first derive a non-stationary spherically symmetric solution describing an expansion of a gas shell under the
pressure of a central source (pulsar). Then, we analyze its 3D stability with respect to a small perturbation on the inner
shell surface. The dispersion relation is derived in the co-moving reference frame. The growth rate of the perturbation is
found and its temporal evolution is discussed. We compare our result with the previous published studies and apply it to the
Crab nebula evolution. 相似文献
5.
近地卫星运动的坐标系附加摄动在拟平均根数法中的处理 总被引：1，自引：0，他引：1
在常用的历元地心天球坐标系中研究和处理近地卫星的轨道问题,就必须考虑由于地球赤道面摆动所引起的坐标系附加摄动,正因为如此,给实际工作带来一些麻烦.关于这一问题,曾提出了一种针对瞬根数和平根数之间的转换(仅与坐标系附加摄动的短周期项有关)的解决途径,但并未涉及采用分析法进行轨道外推的有关问题(这与坐标系附加摄动的长期和长周期项有关),这对处理近地卫星的轨道问题而言显然是不完整的.这里结合拟平均根数法进一步改进原提出的方法,较完善地解决这一坐标系附加摄动的计算问题.在此前提下,对于卫星定轨和预报及其相关工作,无论是采用数值法还是分析法,均可采用同一坐标系,即历元(目前是J2000.0)地心天球坐标系. 相似文献
6.
鉴于ＩＥＲＳ综合河外射电源表在建立ＩＡＵ协议天球参考架方面的重要意义和它们的不足之处，本文重新组建了１９８８至１９９２各年度的综合河外射电源表，称之为Ｃａｔ系列表。并依据综合表的组建原理，对重新计算得到的Ｃａｔ系列表进行了检验，结果表明Ｃａｔ系列表克服了ＩＥＲＳ系列表中坐标系不统一的缺点，指向的定义及维持亦较之ＩＥＲＳ系列表有较大程度地改观。比较结果显示，ＩＥＲＳ系列表中部分源的坐标存在毫角秒量级的偏差，各年度综合表的指向与ＩＥＲＳ预期指向亦有不同程度的偏离，个别轴的最大指向偏差至０．６ｍａｓ。同时指出，１９９３年ＩＥＲＳ综合表的指向亦有待讨论。 相似文献
7.
Celestial coordinate reference systems in curved space-time 总被引：1，自引：1，他引：0
S. M. Kopejkin 《Celestial Mechanics and Dynamical Astronomy》1988,44(1-2):87-115
8.
Anna P. Kartashova 《Earth, Moon, and Planets》2012,108(3-4):165-173
We present a method for calculations of equatorial coordinates of any point in the single frame of the wide-field TV systems. This method can be applying for the different television systems [wide-field cameras, all-sky cameras, the cameras with the hybrid TV-system (the system with coupled of the Image Intensifier) et al.]. In that system the calculations of distortions are difficult. Therefore, we devised this method which helps decrease errors (due to distortion and the electro-optical system).The method can be used for measuring of equatorial coordinates of meteor tracks under difficult conditions during the observations such as partial cloudiness, small number of stars and large distortions of the coordinate grid in the frame. These restrictions cannot be overcome by other methods. In the case of the small number of stars the present method using of the reference stars received on a series of frames during the observation period. The accuracy of the method has been estimated to be 4′–8′ (for cameras with fov 50°?×?40° at the CCD 720?×?576 pixels) for maximum number of reference points in the frame. The method used 3 reference points for calculation of the equatorial coordinates of the object. One can use this method if the camera was re-oriented as well. We use this method for our wide field of view cameras. 相似文献
9.
在简要阐明参考系、参考架及其历史重大进程的基础上,对几种重要的、最新规范的参考系/参考架(质心天球参考系和地心天球参考系、国际天球参考系、国际地球参考系、太阳系动力学参考系等)的定义、实现和特点作了评述和分析,并对最新规范中与参考系、参考架有关的某些新概念的定义和新模式的应用(自2003年开始贯彻),如:天球中介极(CIP)、天球历书原点(CEO)、地球历书原点(TEO)、地球自转角的新定义、岁差-章动新模式的应用,作了阐述和讨论。 相似文献
10.
Rohta Takahashi 《Monthly notices of the Royal Astronomical Society》2007,382(3):1041-1049
Equations of fully general relativistic radiation hydrodynamics in Kerr space–time are derived. While the interactions between matter and radiation are introduced in the comoving frame, the derivatives used when describing the global evolutions of both the matter and the radiation are given in the Boyer–Lindquist frame (BLF) which is a frame fixed to the coordinate describing the central black hole. Around a rotating black hole, both the matter and the radiation are influenced by the frame-dragging effects due to the black hole's rotation. As a fixed frame, we use the locally non-rotating reference frame (LNRF) which is one of the orthonormal frame. While the special relativistic effects such as beaming effects are introduced by the Lorentz transformation connecting the comoving frame and the LNRF, the general relativistic effects such as frame dragging and gravitational redshift are introduced by the tetrads connecting the LNRF and the BLF. 相似文献
11.
The paper deals with the effect of solar pressure on the motion and stability of two satellites connected by an inextensible string in a central gravitational field of force. A system of nonlinear, nonhomogeneous, and non-autonomous equations under the rotating frame of reference in Nechvíle's coordinate system have been obtained. The general solution of the above system of equations is beyond our reach. The particular solutions have been obtained.The particular solution in which the system lies, wholly along the radius vector joining the attracting centre and the centre of mass of the system under the central attracting force along was found to be stable (Singh, 1973). Naturally we got interested in examining the effect of solar radiation pressure on the stability of this particular solution. 相似文献
12.
Yu. I. Morozov 《Astrophysics and Space Science》1987,133(1):107-148
This paper deals with the representation of relativistic equations of gas dynamics with due regard to the general relativity theory effects in the form accepted and widely applied in the special relativity theory. With this purpose, a strict formal definition of a non-inertial co-moving reference frame without rotation is carried out on the basis of a tetrad formalism by use of the Fermi—Walker rules of transport of 4-frame. The equations of physical kinetics, relativistic collapse, Einstein's equations, equations of relatiivistic radiation gas dynamics for ideal and dissipative gases, Taub's equations for a shock wave, which allow for radiation and electron-positron pairs, are obtained in this reference frame. On the basis of the local Lorentz transformation and the Ricci rotation coefficients, these equations are written in the laboratory reference frame, in order to illustrate the fact that the general relativity effects can be simply taken into account in the equations having a form accepted in the special relativity theory. 相似文献
13.
Slawomir Breiter Krzysztof Langner 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):323-342
Kustaanheimo–Stiefel (KS) transformation depends on the choice of some preferred direction in the Cartesian 3D space. This choice, seldom explicitly mentioned, amounts typically to the direction of the first or the third coordinate axis in Celestial Mechanics and atomic physics, respectively. The present work develops a canonical KS transformation with an arbitrary preferred direction, indicated by what we call a defining vector. Using a mix of vector and quaternion algebra, we formulate the transformation in a reference frame independent manner. The link between the oscillator and Keplerian first integrals is given. As an example of the present formulation, the Keplerian motion in a rotating frame is re-investigated. 相似文献
14.
P. K. Seidelmann G. H. Kaplan K. J. Johnston C. M. Wade 《Celestial Mechanics and Dynamical Astronomy》1984,34(1-4):39-48
The weak thermal emission from the largest minor planets can be detected and measured at all points around their orbits at microwave frequencies using the Very Large Array (VLA). Position determinations of astrometric quality have been obtained, and flux measurements have provided size estimates. When enough precise positional observations have been accumulated, the orbits of the minor planets and the Earth can be determined. This will allow the equinox to be located within the radio reference frame, providing a truly fundamental coordinate system for radio source positions. It will also provide a means of relating the optical and radio (quasar) coordinate systems.The National Radio Astronomy Observatory is operated by Associated Universities, Incorporated, under contract with the National Science Foundation. 相似文献
15.
E. F. Arias C. Boucher M. Feissel J. -F. Lestrade 《Astrophysics and Space Science》1991,177(1-2):187-192
The relative orientations of various VLBI celestial reference frames are evaluated on the basis of coordinate differences of common sources. It is shown that an accuracy better than 0.001 can be achieved. Possible regional deformations in the different catalogues are investigated; they are found to reach a few 0.001 in some restricted zones. The application of these studies to the realisation of a combined celestial reference frame consistent with the BIH Terrestrial System is outlined. 相似文献
16.
Colin R. Mcinnes 《Celestial Mechanics and Dynamical Astronomy》1997,67(2):167-180
The two-body problem is considered with an additional thrust induced acceleration. Stationary solutions are obtained to this
problem in a rotating frame of reference which generates families of displaced circular orbits when viewed from an internal
frame of reference. The existence and stability of these orbits is considered along with applications such as in-situ observations
of Saturn's ring system and spacecraft proximity operations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
We report the algorithms used in the software of the upgraded SBG camera. Fast-moving satellites are observed in the “rotated” coordinate system where one of the axes points towards the pole of the object’s orbit. The ephemeris for this coordinate system is computed based on the ephemeris for the equatorial coordinate system using special transition matrices. The parameters of the matrices are the coordinates of the orbital pole, which are found by averaging the vector products of the radius vectors of the consecutive positions of the satellite. The position angle of the image is computed as the difference between the hour angles of the orbital and celestial poles in the coordinate system, the pole of which coincides with the optical center of the frame. The speed of object tracking is computed via quadratic interpolation of the ephemeris in the “rotated” coordinate system. 相似文献
18.
19.
Heinrich Eichhorn 《Celestial Mechanics and Dynamical Astronomy》1984,34(1-4):11-18
A frame of reference is defined asinertial if the coordinates of bodies, predicted with respect to it on the basis of some mechanical principles, agree with those actually observed. It is pointed out that within the framework of Newtonian mechanics the concept of an inertial frame of reference is global, but within the framework of general relativity only local. The relativistic local inertial frame of the Solar System moves with respect to the Newtonian global frame by the amount of geodetic precession. In all rigor, the concept of a globally privileged inertial system has been rendered meaningless by general relativity, even though the concept of an inertial reference frame remains useful in contemporary celestial mechanics. It is further pointed out that none of the practically determined approximations to an inertial frame of reference (e.g., the dynamical reference frame of celestial mechanics, the FK5) must be regarded as adefinition of an inertial system itself. 相似文献
20.
E.F.M. Jochim 《Astronomische Nachrichten》2012,333(8):774-783
Known and unknown properties of Hansen Ideal coordinates are summarized. It is shown that the ideal space frame is a general and necessary component of basic celestial mechanics and astrodynamics, as well as of any theory of motion. A typical consequence is the intimate correlation of the Hansen frame with the Lagrange constraint within the method of the variation of the parameters. The use of observations in the ideal frame may allow conclusions on the intergalactic fundamental coordinate system (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献