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1.
We perform a complete reconstruction of the series of the nutation for a rigid Earth model with the use of the very accurate
theories ELP2000 and VSOP82 for the motion of the Moon and the planets respectively, in such a way that all the individual
contributions up to 0.005 mas should be taken. This implies the introduction of the planetary effects, of the influence of
second-order parts of the potential of the Earth (J3, triaxiality), and some improvements due to an extension of the theory
at the second order. All this increase notably the number of coefficients to be taken in account, and modifies also in a significant
way the value of some of them. 相似文献
2.
V. Dehant M. Feissel P. Defraigne F. Roosbeek J. Souchay 《Geophysical Journal International》1997,130(2):535-546
The observed time-series of precession/nutation show residuals with respect to an empirical model based on the rigid Earth theoretical nutations and a frequency dependent transfer function with resonances to the Earth's normal modes. These residuals display energy mainly in the frequency domain around 430 and 500 days in the inertial frame. In this frequency band, the energy is possibly related to two normalmode frequencies: the free core nutation (FCN) and the free inner core nutation (FICN). In this paper, we examine the possibility of obtaining this energy from the resonance effect induced by a luni-solar (or planetary) forcing, or by an atmospheric forcing at a frequency very close to these Earth free nutations. The amplification factor due to the resonance is computed from an analytical formula expressed in the case of a simplified three-layer ellipsoidal rotating earth (with an elastic inner core, a liquid outer core and an elastic mantle), as well as the empirical formula based on the analysis of VLBI observations. For the tidal forcing, the theoretical results do not show any resonance at the level of precision we have examined but it is still possible to find one frequency near the FCN or FICN frequencies which could be excited. In contrast, for the atmospheric pressure the level of energy needed could be obtained from the diurnal pressure, depending on the noise level of the Earth's global pressure. We also show that the combination of three waves can explain the observed decrease of energy with time. While the tidal potential amplitudes are too small, a pressure noise level of 0.5 Pa would be sufficient to excite these waves. 相似文献
3.
The level of precision of modern numerical ephemeris of the Solar System necessitates taking into account the gravitational
influence of the largest asteroids on the terrestrial planets. This can be done in a straightforward manner when assuming
that the mass of the asteroid is well known. Nevertheless, this is rarely the case, even for the largest asteroids. In this
paper, we use recent determinations of the masses of Ceres, Pallas, and Vesta to both qualitatively and quantitatively determine
the action of these asteroids on the orbital parameters of the Earth and Mars. This is done by the numerical integration by
comparing the orbital motions of the perturbed planet when adding or not the perturbing asteroid to the classical 9 bodies
problem (the Sun + the eight planets). Some preliminary results are discussed.
Published in Russian in Astronomicheskii Vestnik, 2009, Vol. 43, No. 1, pp. 83–86.
The text was submitted by the autors in English. 相似文献
4.
In this paper, the expressions of variations of the dynamical ellipticity and the principal moments of inertia due to the
deformations produced by the zonal part of the tidal potential are obtained. Starting from these expressions, we have studied
from equations related to Hamiltonian theory, their effects on the nutation and finally we have evaluated numerically such
influences, with a level of truncation at 0.1 μas. Thus we have shown that some coefficients are quite large with respect
to the usual accuracy of up-to-date observations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Study of the Correlations Between Long-Periodic Terrestrial Tides and Occurrence of Earthquakes in the Vrancea Site 总被引：1，自引：0，他引：1
Following studies already performed by various authors concerning specific tectonic faults we analyse statistically the possibility
that earthquakes in the very active seismological zone of Vrancea (Roumania) may be triggered by the vertical luni-solar tidal
oscillations when retaining only the components other than diurnal and semi-diurnal. Our conclusion is that for three of the
four leading tides, with periods 18.6 y, 182.62 d, and 13.66 d, the earthquakes occur preferentially during the ascending
part of each of the sine oscillation. This property is especially visible for the leading 13.66 d fortnightly wave, and for
the 18.6 y wave, for which results are very similar to that of Kilston and Knopoff (1983), who analyzed data related to the
San Andreas fault in Southern California. As a complement, we carried out an analysis of earthquake periodicities w.r.t. the
variation rate of each of the tides above, given by the half-period sine oscillation, which also leads to interesting possible
correlations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Marta Folgueira Jean Souchay Hiroshi Kinoshita 《Celestial Mechanics and Dynamical Astronomy》1997,69(4):373-402
In this paper, we calculate the coefficients of the nutation for a rigid Earth model due to the C
3m and S
3m (m ≠ 0) harmonics of the geopotential, starting from the Hamiltonian theory as developped by Kinoshita (1977). We show that
these coefficients are far from being negligible as given the level of truncation of 0.1 μas which is necessary in the reconstruction
of the tables of nutation, and also that their value is very close to that given by Bretagnon et al. (1997).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Effects of the Triaxiality on the Rotation of Celestial Bodies: Application to the Earth,Mars and Eros 总被引：1，自引：0，他引：1
In this paper we discuss the influence of the triaxiality of a celestialbody on its free rotation, i.e. in absence of any external gravitationalperturbation. We compare the results obtained through two different analytical formalisms, one established from Andoyer variables by usingHamiltonian theory, the other one from Euler's variables by usingLagrangian equations. We also give a very accurate formulation of thepolar motion (polhody) in the case of a small amplitude of this motion.Then, we carry out a numerical integration of the problem, with aRunge–Kutta–Felberg algorithm, and for the two kinds of methods above, that we apply to three different celestial bodies considered as rigid : the Earth, Mars, and Eros. The reason of this choice is that each of this body corresponds to a more or less triaxial shape.In the case of the Earth and Mars we show the good agreement betweenanalytical and numerical determinations of the polar motion, and theamplitude of the effect related to the triaxial shape of the body, whichis far from being negligible, with some influence on the polhody of theorder of 10 cm for the Earth, and 1 m for Mars. In the case of Eros, weuse recent output data given by the NEAR probe, to determine in detailthe nature of its free rotational motion, characterized by the presence ofimportant oscillations for the Euler angles due to the particularly largetriaxial shape of the asteroid. 相似文献
8.
Thanks to the recent data obtained from the NEAR space probe, we calculate in this paper, with a precision never reached so far for an asteroid, the precession and the nutation of Eros 433. In a preliminary step, we show that Eros obliquity has a remarkable value of 89.0° which tends to align its figure axis along the orbital plane. This very specific obliquity has some consequences on the motion of the axis of figure: one is the very small amplitude of the precession in longitude, for which we get the value . Moreover, we calculate Eros nutation for the figure axis due to the Sun, after developing the perturbing potential at the 4th order of the eccentricity. We show that the figure axis undergoes very large oscillations in the direction perpendicular to Eros orbital plane, due to the nutation in obliquity. Peak to peak, these oscillations reach 55″, which is far larger than the amplitudes of the nutations of the Earth due to the Sun (of the order of 2″). Moreover, we give the analytical developments of Δψ and Δε, both for the axis of angular momentum, and the axis of figure. 相似文献
9.
M. Folgueira CH. Bizouard J. Souchay 《Celestial Mechanics and Dynamical Astronomy》2001,81(3):191-217
We present a comparison of the diurnal and subdiurnal terms of the three last theories of rigid Earth's rotation: SMART97, RDAN97 and REN 2000. For a better interpretation of the observations, we characterize their contribution to the polar motion and we estimate the non-rigid effects, which are at the level of a few microarcseconds. 相似文献
10.
F. Arias Ch. Bizouard P. Bretagnon A. Brzezinski B. Buffett N. Capitaine P. Defraigne O. de Viron M. Feissel H. Fliegel A. Forte D. Gambis J. Getino R. Gross T. Herring H. Kinoshita S. Klioner P.M. Mathews D. Mccarthy X. Moisson S. Petrov R.M. Ponte F. Roosbeek D. Salstein H. Schuh K. Seidelmann M. Soffel J. Souchay J. Vondrak J.M. Wahr P. Wallace R. Weber J. Williams Y. Yatskiv V. Zharov S.Y. Zhu 《Celestial Mechanics and Dynamical Astronomy》1998,72(4):245-309
This paper presents the reflections of the Working Group of which the tasks were to examine the non-rigid Earth nutation theory. To this aim, six different levels have been identified: Level 1 concerns the input model (giving profiles of the Earth's density and theological properties) for the calculation of the Earth's transfer function of Level 2; Level 2 concerns the integration inside the Earth in order to obtain the Earth's transfer function for the nutations at different frequencies; Level 3 concerns the rigid Earth nutations; Level 4 examines the convolution (products in the frequency domain) between the Earth's nutation transfer function obtained in Level 2, and the rigid Earth nutation (obtained in Level 3). This is for an Earth without ocean and atmosphere; Level 5 concerns the effects of the atmosphere and the oceans on the precession, obliquity rate, and nutations; Level 6 concerns the comparison with the VLBI observations, of the theoretical results obtained in Level 4, corrected for the effects obtained in Level 5.Each level is discussed at the state of the art of the developments. 相似文献