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A discussion is presented about the constraints used in constructing a model for the internal structure of Mars. The most important fact is that the Martian chemical model proposed by Wänke and Dreibus (WD) has stood the test of time. This means that the chondritic ratio Fe/Si = 1.71 can be used as a constraint in constructing an interior structure model of the planet. Consideration is given to the constructing of the reference surface of Mars. It is concluded that the effectively hydrostatic-equilibrium model of Mars is well suited for this purpose. The areoid heights and gravity anomalies in the model of Mars are calculated. The results are shown in the figures (maps) and comments made. The results are compared with the similar data for the Earth. Mars deviates much more strongly from the hydrostatic equilibrium than the Earth. It is suggested that the average thickness of the Martian elastic lithosphere should exceed that of the Earth’s continental lithosphere. 相似文献
3.
On the scientific aims of the MISS seismic experiment 总被引:1,自引:0,他引:1
The paper deals with how the data on structure of the Martian near-surface layers and deep interiors can be obtained using the only broadband seismometer in the framework of the planned MISS (Mars Interior Structure by Seismology) experiment. For this purpose, both traditional and nontraditional seismic methods of interior sounding are used. These methods process meteorite impact data, seismic noise from meteorological effects, and the data from strong Martian lithoshere quakes. 相似文献
4.
V. N. Zharkov 《Earth, Moon, and Planets》1983,29(2):139-175
A survey is made of the physics of the interiors of Venus. The introduction explains the main concepts used in the construction of models of Venus and the history of the question; observational data are gathered and analyzed. The method of constructing the models of the planet is explained and earth-like models of Venus and parametrically simple PVM models are discussed. Within the compass of a physical nodel of Venus, the thermodynamics of the mantle and core is constructed and questions are discussed concerning the heat conduction, temperature distribution in the lithosphere and the thermal flux from the interior of Venus, the electrical conduction and mechanical quality, and large-scale steady stresses in the mantle of Venus. A rheological model of the crust and mantle is constructed. In conclusion, the question as to the distribution of radioactivity and convection in the interior of the planet is discussed. 相似文献
5.
We consider two-layer (Fe-FeS core+silicate mantle) and three-layer (Fe-FeS core+silicate mantle+crust) models of the Galilean satellite Io. Two parameters are known from observations for the equilibrium figure of the satellite, the mean density ρ0 and the Love number k2. Previously, the Radau-Darwin formula was used to determine the mean moment of inertia. Using formulas of the Figure Theory, we calculated the principal moments of inertia A, B, and C and the mean moment of inertia I for the two-and three-layer models of Io using ρ0 and k2 as the boundary conditions. We concluded that when modeling the internal structure of Io, it is better to use the observed value of k2 than the moment of inertia I derived from k2 using the Radau-Darwin formula. For the models under consideration, we calculated the Chandlerian wobble periods of Io. For the three-layer model, this period is approximately 460 days. 相似文献
6.
Two types of trial three-layer models have been constructed for the satellites Io and Europa. In the models of the first type (Io1 and E1), the cores are assumed to consist of eutectic Fe-FeS melt with the densities ρ 1 = 5.15 g cm?3 (Io1) and 5.2 g cm?3 (E1). In the models of the second type (Io3 and E3), the cores consist of FeS with an admixture of nickel and have the density ρ 1 = 4.6 g cm?3. The approach used here differs from that used previously both in chosen model chemical composition of these satellites and in boundary conditions imposed on the models. The most important question to be answered by modeling the internal structure of the Galilean satellites is that of the condensate composition at the formation epoch of Jupiter’s system. Jupiter’s core and the Galilean satellites were formed from the condensate. Ganymede and Callisto were formed fairly far from Jupiter in zones with temperatures below the water condensation temperature, water was entirely incorporated into their bodies, and their modeling showed the mass ratio of the icy (I) component to the rock (R) component in them to be I/R ~ 1. The R composition must be clarified by modeling Io and Europa. The models of the second type (Io3 and E3), in which the satellite cores consist of FeS, yield 25.2 (Io3) and 22.8 (E3) for the core masses (in weight %). In discussing the R composition, we note that, theoretically, the material of which the FeS+Ni core can consist in the R accounts for ~25.4% of the satellite mass. In this case, such an important parameter as the mantle silicate iron saturation is Fe# = 0.265. The Io3 and E3 models agree well with this theoretical prediction. The models of the first and second types differ markedly in core radius; thus, in principle, the R composition in the formation zone of Jupiter’s system can be clarified by geophysical studies. Another problem studied here is that of the error made in modeling Io and Europa using the Radau-Darvin formula when passing from the Love number k 2 to the nondimensional polar moment of inertia $\bar C$ . For Io, the Radau-Darvin formula underestimates the true value of $\bar C$ by one and a half units in the third decimal digit. For Europa, this effect is approximately a factor of 3 smaller, which roughly corresponds to a ratio of the small parameters for the satellites under consideration α Io/α Europa ~ 3.4. In modeling the internal structure of the satellites, the core radius depends strongly on both the mean moment of inertia I* and k 2. Therefore, the above discrepancy in $\bar C$ for Io is appreciable. 相似文献
7.
We investigate the emergence of Active Region NOAA 10790 by means of time?–?distance helioseismology. Shallow regions of increased sound speed at the location of increased magnetic activity are observed, with regions becoming deeper at the locations of sunspot pores. We also see a long-lasting region of decreased sound speed located underneath the region of the flux emergence, possibly relating to a temperature perturbation due to magnetic quenching of eddy diffusivity, or to a dense flux tube. We detect and track an object in the subsurface layers of the Sun characterised by increased sound speed which could be related to emerging magnetic-flux and thus obtain a provisional estimate of the speed of emergence of around 1 km?s?1. 相似文献
8.
Izvestiya, Physics of the Solid Earth - We analyze nonhydrostatic stress field in the Martian interior for two types of heterogeneous elastic models: the ones with a lithosphere and the ones with a... 相似文献
9.
The distribution of BATSE-events over the sky is studied by the method based on the probability theory. The short presentation of the method is given. The results might indicate the presence of some anomaly in a broad region around the Andromeda nebula. 相似文献
10.
A general theory for the figures of satellites, which are synchronously rotating in the gravitational field of a planet, is developed to the first approximation. Love numbers, figure parameters, and gravitational moments for two- and three-layer models of the Galilean satellites, Titan, and Saturn's icy satellites are calculated. With the assumed accuracy for flyby measurements of gravitational moments it should be possible to determine the degree of differentiation of Ganymede. The differences between equatorial a and polar c semiaxes, as derived from the observational data, appear to be exaggerated for Io and Mimas (although better agreement between calculated and observed values of (a?c) could be obtained if this satellite had a larger mass). For Enceladus the observed value of (a?c) is in satisfactory agreement with calculations, based on different types of trial models. However, in order to discriminate between different Enceladus trial models, it is necessary to determine the figure parameters more precisely. 相似文献