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1.
An idea is developed that the vacuum in the gravitational field acquires properties of an elastic medium described by a definite tension
ik
. The vacuum is stated to also participate in the formation of the space-time metric, together with the usual matter. So, the matter, vacuum and metric form a complex unity determined by the solution of the field equations. The vacuum may prove to play an essential role in the extremely strong fields existing in superdense celestial bodies. The tensor
ik
is not to be identified with the pseudo-tensor of the energy-momentum of the gravitational field the idea of which is preserved.The problem of vacuum is investigated in the case of the central symmetry static field. A number of properties of the tensor
ik
is found using the symmetry of the field and comparison with the post-Newton limit. The external and internal problems, as well as the procedure of joining the solutions on the surface of a celestial body, have been formulated. The stellar surface is determined in the usual way:P(r) = 0 whereP is the matter pressure. The theory includes three dimensionless parametersa=p/,b=p
/ (,p, p
are the density of the vacuum energy and of its pressures in the radial and transverse directions) and determining the vacuum elastic properties. Generally speaking, they depend on the valueP/c2 in the stellar centre where is the mass density. From general physical considerations it is shown that 0 1 + lim
P (l/q). The field equations are solved for the simple version of the theoryb=–a. There are solutions corresponding to superdense celestial bodies with masses considerably exceeding that of the Sun. 相似文献
2.
The 5-dimensional Jordan-Brans-Dicke cosmologies in vacuum are found for the Bianchi type I metric, their relation with general relativity cosmologies is studied. Two solutions are possible, both produce effective pressure and energy density in the 4-dimensional G.R.-universes. One is a power-law relation, with two cases, the first one is forp
eff=eff and the other forp
eff=eff(– 1 < < 1) has a behaviour as the open flat universe. The second solution is an exponential only valid forp
eff=–eff. In all cases the three-space expansion reaches infinity ast and the fifth dimension can be made to decrease approaching zero. The scalar field can increase or decrease with time. 相似文献
3.
By solving the Euler hydrodynamical equations we have obtained closed form solutions for the angular velocities and pressures of a three stratified non-confocal heterogeneous oblate spheroid. Limiting and particular solutions cases, such as a spheroid with N layers, a stratified spheroid with the same eccentricities, as well as confocal layered spheroids are also explicitly written down. As an application, we have numerically estimated planet Earth's outer and inner cores' ellipticities to be o=1/413.318 and i=1/424.616, respectively. These Earth's ellipticities values are in good agreement with those found in the literature. 相似文献
4.
Two new Th ii lines have been identified in the spectrum of the solar photosphere. The abundance derived from these lines together with the previously known Th ii line at 4019 Å, is log
Th = 0.85 ± 0.20 in the log
H = 12.00 scale. Analysis of three Pb i lines in the photospheric spectrum resulted in an abundance of log
pb = 1.90 ± 0.10. The solar Th/Pb ratio is:
Th/
Pb = 0.09
-0.005
0.09
. 相似文献
5.
M. -J. Martres 《Solar physics》1970,11(2):258-262
Résumé Il existe une certaine symétrie dans l'évolution des Centres Actifs (C.A.) simples nés à l'est (p) ou à l'ouest (f) d'un centre ancien.Dans l'un et l'autre cas, les taches directement exposées à la polarité inverse du C.A. ancien deviennent les taches de plus grande surface du groupe: tache de tête Tt des p, tache de queue Tq des f.Dans le même temps leur mouvement propre tend à les rapprocher du centre ancien. Les déplacements en longitude sont supérieurs, en valeur absolue, aux déplacements moyens des taches homologues d'un C.A. isolé. Les différences ainsi mesurées sont les mêmes pour les Tt ou les Tq et égales à environ 1°.5 en 3 jours pour les groupes de l'échantillon choisi, les déplacements mesurés étant en moyenne de l'ordre de 3°.
Following the study of anomalies in spot groups correlated to the existence of an older active center (A.C.) in the same region, we compared the evolution of 50 A.C. of simple magnetic configuration or .We associated the growth and the proper motion of their spots to the absence or the presence of an A.C. in the vicinity, and in that eventuality to the relative disposition of the two A.C. in presence.We find that a group situated to the west of an older one evolves to the type f and shows an eastward motion of the following spot greater than in the case of an isolated group.Symmetrically, the evolution to p of a group situated to the east of the original formation is associated with a westward motion of the leading spot greater than in the case of an undisturbed group.The difference between those displacements and the average ones corresponding to an isolated A.C. is the same in both cases and is equal to about 1°.5 in three days for the groups of the sample chosen.相似文献
6.
J. Horn 《Astrophysics and Space Science》1970,6(3):492-496
Evolution of a binary system with masses of 5m
and 4m
, respectively, and with orbital period of 1.41 days is studied by means of non-stationary model calculations under assumptions of conservation of total mass and total orbital angular momentum of the system. As a result of mass exchange between the components we obtain a binary with masses of 8.46 and 0.54m
. Physical parameters of the final product indicate possible connection with shell stars.It is also pointed out that the new secondary component can become rotationally unstable soon after the end of mass exchange. 相似文献
7.
In this paper we present exact solutions to the density perturbation equation derived by Bonnor for the cases where =
c
,k=1 and = –
c
,k=–1. The solutions when =0,k=1 and =0,k=–1 have been previously published. Using these solutions a quantitative analysis has been carried out that has enabled us to estimate the size of the fluctuations that must be postulated at decoupling in order to explain the formation of the galaxies in these model universes. 相似文献
8.
We describe global bifurcations from the libration points of non-stationary periodic solutions of the restricted three body problem. We show that the only admissible continua of non-stationary periodic solutions of the planar restricted three body problem, bifurcating from the libration points, can be the short-period families bifurcating from the Lagrange equilibria L
4, L
5. We classify admissible continua and show that there are possible exactly six admissible continua of non-stationary periodic solutions of the planar restricted three body problem. We also characterize admissible continua of non-stationary periodic solutions of the spatial restricted three body problem. Moreover, we combine our results with the Déprit and Henrard conjectures (see [8]), concerning families of periodic solutions of the planar restricted three body problem, and show that they can be formulated in a stronger way. As the main tool we use degree theory for SO(2)-equivariant gradient maps defined by the second author in [25].This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
9.
Vladimir Pletser 《Earth, Moon, and Planets》1986,36(3):193-210
Résumé Une formulation exponentielle de la loi empirique de Titus-Bode a été proposée par Basano et Hugues. Ces auteurs introduisent l'hypothèse de trois planètes manquantes ou trous. Toutes les planètes obéissent à la relation a
n
=
n
qui donne les demi-grands axes a des planètes pour des valeurs entières de n.Nous proposons une nouvelle méthode qui permet de retrouver la relation de Basano et Hugues pour le système solaire. Nous appliquons cette méthode aux systèmes de satellites de Jupiter, Saturne et Uranus en introduisant des trous pour combler les lacunes dans les séquences de satellites. Nous en tirons trois relations exponentielles de distance, analogues à la relation de Basano et Hugues. Nous constatons que les coefficients sont semblables pour les systèmes solaire, jovien et uranien alors que le coefficient du système de Saturne vaut approximativement la racine carrée des trois autres .Nous expliquons cet espacement exponentiel grâce à un modèle simple d'une nébuleuse gazeuse initiale soumise à de petites perturbations qui engendrent des oscillations dans la distribution de densité. Les minima de la densité perturbée sont donnés par les zéros des fonctions de Bessel décrivant la propagation de la perturbation. Les positions des maxima correspondent aux sites d'accrétion.Tous les trous introduits dans les parties intérieures des systèmes de satellites sont comblés par les anneaux et petits satellites. Dans le système d'Uranus, il reste deux trous vacants qui pourraient être occupés par des petits satellites non encore découverts.
Exponential distance laws for satellite systems
A revised Titius-Bode law for the Solar system was proposed by Basano and Hugues, by introducing three missing planets. This law can be written a n = n (with = 0.2853 AU and = 1.5226), which gives the distances a n of the nth planet for successive integers n.We propose a new method to find this Basano-Hugues law for the Solar system. Based upon the comparison of the ratios of successive distances, this method can be applied to the satellite systems of the three giants planets Jupiter, Saturn and Uranus by introducing missing satellites to fill the gaps in satellites sequences. We find three exponential distance relations, similar to that of Basano-Hugues. We note that the coefficients for the Solar, Jovian and Uranian systems are almost equal while the Saturnian system's coefficient is nearly the square root of that of the three others.We explain that exponential spacing by a simple model of an initial gaseous nebula subject to small perturbations generating oscillations in the density distribution. The minima of the perturbed density are given by the zeros of Bessel functions describing the perturbation propagation. The maxima positions correspond to accretion sites.All the empty places in the inside parts of satellite systems are occupied by rings and small satellites. In the Uranian system, there are two empty places which could be filled by new undiscovered small satellites.相似文献
10.
Computations of polarization and intensity of radiation from a unit stellar surface area are presented, as well as a study of the numerical characteristics of atmospheres — single-scattering albedo and the initial source function(), which define the polarization behaviour of atmospheres. The radiatively stable models of stellar atmospheres presented by Kuruczet al. (1974) and Kurucz (1979) have been used for calculations. Since the versus optical depth dependence is rather weak, it has been assumed that (=cost. With a fixed effective temperatureT
eff maximum values of are characteristic of stars featuring the lowest surface gravity accelerationg. Among stars with radiatively stable atmospheres, maximum values of (=5000 Å) 0.4–0.6 are exhibited by supergiants withT
eff=8000–20 000 K. The plot of () is characterized by discontinuities at the boundaries of spectral series for hydrogen and, sometimes, for helium. Maximum are attained in the Lyman region of =912–1200 Å, where can reach the value 0.7–0.9 for supergiants, this value being 0.3 for Main-Sequence stars. For stars withT
eff 35 000 K, high values of also are attained for <912 Å. Within the infrared region, is always small because of bremsstrahlung absorption.A rapid growth of the source functionB
with < typical for ultraviolet range (within the Wien part of spectrum), together with high values of results in the strong polarization of emission from a unit stellar surface element, sometimes exceeding the values for the case of a pure electron scattering. For longer wavelengths, where the limb-darkening coefficient is smaller, the plane of polarization abruptly turns 90° in the central parts of the visible stellar disk. 相似文献
11.
Until recently far infrared (FIR) observations of galaxies were limited to about a dozen bright and/or active galaxies. New photometric data has become available from Infrared Astronomical Satellite (IRAS) on 33 galaxies (most of them faint) from IRAS Circular Nos. 1, 2, and 3 The FIR spectra of these galaxies are similar. The far infrared fluxF
FIR in the wavelength interval 9–118 m of the brighter galaxies is seen to be correlated with the integrated optical magnitudeB
T
0
. The 12 and 25 m fluxes of these galaxies exhibit the same dependence onB
T
0
as the 10 and 21 m fluxes from Seyferts and other emission-line galaxies. This suggests that the galaxies detected by IRAS are some type of active galaxies in accord with the high percentage of these galaxies predicted by Lock and Rowan-Robinson (1983). 相似文献
12.
P. G. D. Barkham V. J. Modi A. C. Soudack 《Celestial Mechanics and Dynamical Astronomy》1977,15(1):5-20
A small particle moves in the vicinity of two masses, forming a close binary, in orbit about a distant mass. Unique, uniformly valid solutions of this four-body problem are found for motion near both equilateral triangle points of the binary system in terms of a small parameter , where the primaries move in accordance with a uniformly-valid three-body solution. Accuracy is maintained within a constant errorO(8), and the solutions are uniformly valid as tends to zero for time intervalsO(–3). Orbital position errors nearL
4 andL
5 of the Earth-Moon system are found to be less than 5% when numerically-generated periodic solutions are used as a standard of comparison. 相似文献
13.
K. M. Aggarwal 《Solar physics》1984,94(1):75-84
Using theR-matrix approach new calculations have been made for the electron impact excitation of the fine structure transitions within the 1s
22s
22p
2 ground configuration of Mgvii. The computations have been made at a large number of energies in order to account for the contribution of resonances. All partial waves withL 9 are included in the calculations which are considered to be sufficient for the convergence of collision strengths in the energy range below 65 Ry. From this collision strength data, excitation rate coefficients have been calculated at a series of electron temperatures which are employed in the computation of population of the five lowest levels of Mgvii. The line intensity ratios for the transitions3
P
1 1
D
2 and3
P
2 1
D
2 to3
P
1 1
S
0 are then calculated in the temperature range of 105 to 107 K at electron densities in the range 106 to 1010 cm–3. The calculated values are in good agreement with the earlier available results. 相似文献
14.
C.P. Singh 《Astrophysics and Space Science》2001,275(4):377-383
A spatially homogeneous and isotropic Robertson-Walker model withzero-curvature of the universe is studied within the frame-work of Lyra'smanifold. The gauge-function in Lyra's manifold is taken to betime-dependent. Exact solutions of Einstein equations are obtained for twodifferent early phases of the universe viz. Inflationary phase andradiation-dominated phase by using `gamma-law' equation of statep = ( - 1) . The -index, describing the material content,varies continuously with cosmic time so that in the course of itsevolution, the universe goes through a transition from an inflationaryphase to a radiation-dominated phase. The physical properties of themodels are also discussed. 相似文献
15.
H. J. Fahr 《Solar physics》1973,30(1):193-206
The effect of a new energy source due to energies transferred from supra-thermal secondary ions on the temperature profile of the solar wind has been considered. For this purpose a solution of a tri-fluid model of the solar wind including solar electrons, protons, and -particles, and starting with the boundary conditions of Hartle and Barnes at 0.5 AU is given. On the base of the assumption that suprathermal He+-ions which have four times the temperature of suprathermal protons are predominantly coupled to solar -particles by Alfvén waves, it is shown that the temperature T
of solar -particles should be appreciably higher than those T
p of solar protons beyond the orbit of the Earth. For 1 AU a temperature excess T
over T
p according to that which has been found in some solar wind ion spectrograms can only be explained for a small part of the orbit of the earth which is inside the cone of enhanced helium densities. Around 1 AU the temperatures T
and T
p are found to decrease much slighter with solar distance than given in the two-fluid model of Hartle and Barnes. Beyond 1.7 and 2.2 AU the temperatures T
and T
p even start increasing with solar distance and come up to about 105 at about 10 AU. These predictions should lend some support to future temperature measurements with deep-space probes reaching Solar distances of some AU.Forschungsberichte des Astronomischen Institutes, Bonn, 72-10. 相似文献
16.
R. Caimmi 《Astrophysics and Space Science》1993,209(1):1-17
The present attempt aims to predict the dependence of the spin parameter, , the angular momentum,J, and the typical radius,a
vir, on the mass,M, which have been found inN-body simulations of expanding density perturbations in hierarchical clustering, when virialization is attained. We show that M
0 for systems with same adimensional density distribution and velocity distribution, and in particular for scale-free density perturbations in hierarchical clustering. In the special case of ellipsoidal perturbations, it is also found:J M
7/4,a
vir M
1/2. All these results turn out to be in close agreement withN-body simulations, despite the simple model adopted. Expanding and virialized perturbations are modelled, respectively, by homogeneous and heterogeneous, similar ellipsoids which allow flat rotation curves far from the centre. Both energy and angular momentum maintain from a given time on, lying between the beginning of strong decoupling from the Hubble flow and the occurrence of maximum volume. Then the whole set of virialized ellipsoidal configurations with same energy and angular momentum are derived, and the dependence of the spin parameter on the anisotropy parameter, pec is investigated. Turning our attention to the formation of galaxies, we derive the total mass as a function of the collapse factor, using the empirical anticorrelation between dark to visible mass ratio within the optical radius of disk galaxies and their luminous masses. Observational data related to a sample of elliptical galaxies provide evidence that the contraction in these bodies occurred in proportion to the square root of the ratio of total to luminous mass. On the contrary, it is deduced that dissipation of angular momentum in elliptical galaxies occurred more or less at the same rate. If both shape and anisotropy parameter are preserved during the collapse, typical axis rations 21 = 0.98, 31 = 0.69, are found to correspond to a moderate anisotropy, pec 0.27, with a small dependence on the spin parameter in the range allowed. 相似文献
17.
We apply the MINOS optimization system to the population synthesis of galactic nuclei, using a grid of star cluster equivalent widths as a function of age and metallicity. For some classes of red galaxy nuclei, this observational approach to population synthesis produces results similar to those predicted by the theoretical approach of Arimoto and Yoshii (1987). The synthesis results for blue nuclei tend to scatter more in the age vs metallicity plane, probably because we use only visible and near-infrared spectral data. Additional information at shorter wavelengths will possibly produce better-focused solutions in the plane. However, strong bursts of star formation can easily be identified. We provide in this contribution population synthesis for the central regions of M31 and M32. The bulge and the semi-stellar nucleus of M31 are dominated by the old metal-rich population: the semi-stellar nucleus has reached up [Z/Z
]0.6 and the bulge [Z/Z
]0.3. In the central region of M32, a metallicity up to the solar value has been reached and the synthesis indicates that the intermediate age component is not dominant. 相似文献
18.
19.
K. T. Alfriend 《Celestial Mechanics and Dynamical Astronomy》1971,4(1):60-77
The stability ofL
4 and the motion aboutL
4 in the restricted problem of three bodies is investigated when there is three-to-one commensurability between the long and short periods of motion, that is, when the mass ratio has the value =0.013516.... The two time scale method is used (1) to show thatL
4 is an unstable equilibrium point when =3, (2) to determine for what initial conditions periodic orbits occur when 3, (3) to determine the stability of the periodic orbits, and (4) to investigate the boundedness of the motions aboutL
4 when 3. 相似文献
20.
The effect of a uniform magnetic field on the envelope convection zone of an 8.8M
star has been studied. The adiabatic exponents
i
(i=1, 2, 3), adiabatic temperature gradient and specific heat of stellar matter has been computed. It is shown that the magnetic field tends to increase the values of adiabatic temperature gradient and specific heats of stellar matter in the envelope convection zone. 相似文献