共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
In this paper, we calculate the astronomical effects that accrue in the equatorial plane of a stellar object due to rotation according to Kerr theory.Dedicated in honour of Professor A. K. Raychaudhuri who derived the Raychaudhuri equation in Cosmology. 相似文献
3.
P. K. Seidelmann 《Celestial Mechanics and Dynamical Astronomy》1996,66(1):97-106
The introduction of the extragalactic reference frame and the availability of the Hipparcos and Tycho catalogs will have major impacts on changing the accuracy levels of astrometry in the future.There is a need for accurate densification of the reference frames down to at least 20th magnitude, Also accurate space motions and distances will be required. The ground based observations must be supplemented by space missions. In addition to traditional positional astrometry, the scientific applications of planetary detection, distance scales, multiple star systems, mass detections, solar system motions and geodesy will be advanced by the new accuracies. 相似文献
4.
Qualitative analysis is given of the second integrals of the equations of geodesics of the Kerr metric expressed in the Boyer-Lindquist coordinates. 相似文献
5.
《New Astronomy》2021
We have found an approximate solution of Dirac equation using Foldy-Wouthuysen-Tani Hamiltonian of a Dirac particle in the Kerr gravitational field. We have solved the equation approximately using time-independent perturbation theory for the positive energy states. We have found frequencies by which these states oscillate. Difference of the periods of any of these two states has an identical form of the classical gravitomagnetic clock effect where the terms are quantized. So that, we have found a quantum version of the gravitomagnetic clock effect of a Dirac fermion in the Kerr gravitational field. 相似文献
6.
7.
8.
未来10年天体测量的发展 总被引:1,自引:0,他引:1
首先回顾了依巴谷卫星的观测结果在天文学上的意义,同时指出其不足之处,极限星等仅为 12mag,自行精度不够高等,介绍了正在进行的各种地面上的暗星扩充计划,如TAC、SDSS、UCAC-S,POSS等,并对它们的预期计划和目前进展情况作了详细描述。叙述了未来10年可能实施的几个空间天体测量计划,如欧洲空间的GAIA,美国喷气推进实室的SIM,德国的DIVA,美国海军天文台的FAME和俄罗普尔科沃天文 相似文献
9.
10.
O. Semerák 《Monthly notices of the Royal Astronomical Society》1999,308(3):863-875
Mathisson–Papapetrou equations are solved numerically to obtain trajectories of spinning test particles in (the meridional section of) the Kerr space–time. The supplementary conditions p σ S μσ =0 are used to close the system of equations. The results show that in principle a spin-curvature interaction may lead to considerable deviations from geodesic motion, although in astrophysical situations of interest probably no large spin effects can be expected for values of spin consistent with a pole–dipole test-particle approximation. However, a significant cumulative effect may occur, e.g. in the inspiral of a spinning particle on to a rotating compact body, that would modify gravitational waves generated by such a system. A thorough literature review is included in the paper. 相似文献
11.
欧洲空间局正在考虑的空间天体测量卫星计划(GAIA计划)将对目视星等V亮于15.5mag的5千万颗目标进行位置、自行和视差的测定,其精度为10μas,同时还对这些目标进行多色多历元光度测定.该计划可对星系距离尺度、恒星演化、银河系运动学和动力学以及参考架联结等方面进行深入研究.其开创的微角秒天体测量学亦将会对天体物理学、太阳系天体和参考架联结等方面的研究产生深远的影响. 相似文献
12.
P. Bhaskaran S. C. Tripathy A. R. Prasanna 《Journal of Astrophysics and Astronomy》1990,11(4):461-474
In this paper we discuss the equilibrium configuration of a plasma disc of infinite conductivity around a slowly rotating
compact object, and obtain the pressure profiles, and the structure of magnetic field lines for co and counter-rotating discs. 相似文献
13.
Henry E. Kandrup 《Astrophysics and Space Science》1983,97(2):435-452
An exact formula is derived for the average frictional force acting upon a ‘test’ star which moves along a prescribed trajectory amongst a collection of ‘field’ stars which are characterized by a Maxwellian distribution of velocities. In the limit that the actual stellar trajectories may be approximated by their average forms, as determined by the mean gravitational field, one obtains a relatively simple expression which establishes an important connection with the fluctuation-dissipation theorem. For the case of an infinite, homogeneous system, one recovers Chandrasekhar's classical result. Alternatively, by allowing for the possibility of nearly periodic motion, one is led to new and intriguing phenomena. 相似文献
14.
15.
M.A. Pérez-Torres J.M. Marcaide J.C. Guirado E. Ros 《Astrophysics and Space Science》1998,263(1-4):311-314
We observed the pair of radio sources 1150+812 and 1803+784 in November 1993 with an intercontinental array of radio telescopes,
simultaneously recording at 8.4 and 2.3 GHz, using the very-long-baseline interferometric technique. We determined the angular
separation between the two sources with submilliarcsecond accuracy by using differential techniques. This result validates
the feasibility of high precision differential astrometry for radio sources separated in the sky by almost 15°, and opens
the avenue to its application to larger samples of radio sources.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
The young open star cluster M25 (IC 4725) is located in the direction of the galactic center, near much irregular absorption
features on Sagittarius arm. This system is found to be at a distance of 600 pc, with a median age of 9.45 × 107 years and a distance from the galactic plane of –52.82 pc The mass data available in the literature has been gathered and
many statistical methods have been applied for this cluster. Depending only on these methods, the stellar density, the distribution
of dark matter, the luminosity and the mass functions have been estimated. The center of the cluster has been defined, it
is shifted by 45 arc sec in the northeast direction. The radius of the cluster is found to be 4 pc. More than 220 stars with
mean reddening of 0.50 mag and absorption of 1.62mag are found inside this aria. The total mass of the cluster has been estimated
with the mass of the interstellar matter (gas and dust). It is found to be 1937 M
⊙, whereas about 24% of the material mass of the cluster has remained as interstellar matter after the processes of formation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
18.
19.
M. Marie 《Astrophysics and Space Science》1993,201(1):71-77
New proper motion membership probabilities are given for stars in the region of the cluster NGC 2324. The space density distribution and the luminosity function are discussed. A comparison with previous investigations is presented. 相似文献