The application of a non-static spherically-symmetric metric to clusters of galaxies

An approximate metric is found which represents a sphere of matter embedded in a background of dust. The use of this metric in conjunction with the Friedmann equations gives values of for the three possible values ofk as +6×10^–36 (k=+1), +3×10^–35 (k=0), +10^–36 (k=–1). These values depend on data regarding clusters of galaxies, and are probably accurate to within an order of magnitude given the correctness of the assumptions on which their derivation rests.     

Anisotropic viscous universe with variableG and Λ

An anisotropic model with variableG and and bulk viscosity is considered. The model exhibits an inflationary behavior during which the coefficient of bulk viscosity varies lineraly with the energy density. This allows the anisotropy energy to decrease exponentially with time. Other results overlap with our earlier work with a different ansatz for . The gravitational constant was found to increase during the radiation and matter epochs.     

The rate of growth of density perturbations in simple big-bang model universes

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.     

Оπорная селенодезическая система координат по гелиометрическим наБлюдениям луны В казани

, 1969–1975 .., 32 . , .     

Набλюдатрльльй подхои к ранним ста диям эволюции звезд

. . u . . . ]qi . , , . . (, , , , -). . , . , . FU ) - ).     

Перенос поляризации излучения В магнитоактивной космической плазме

u , . , .. (1.10), (1.2) ( (1.2)) . (1964) . (1.10), , , , (1.13). , , S _iq ,R _iglm ,K _iqlm (1.10) . , . . , (1.3), (2.3); (2.8)–(2.10). , , , , z (2.20), .. , , (. (2.15)). (K _{e, 0} ) . ^S , ( (2.24)). (2.24a) ^S ±/4. , , (K _{e, o}<0). L, — , , ; , . .     

Horizontal-branch star models

Evolutionary tracks of 0.9M , 0.7M and 0.6M models for Population II stars have been computed in the post-red giant phase. The stars are initially composed of a helium core containing a mass fraction equal to 0.9 and of a hydrogen-rich envelope. They represent hypothetical remnants of stars after substantial mass loss in previous evolutionary phases or/and at the helium flash.u 0,9M , 0,7M 0,6M . , 90% , . , .Riassunto È stata calcolata per modelli di stelle di 0,9M , 0,7M e 0,6M di Popolazione II l'evoluzione successiva allo stadio di gigante rossa. Inizialmente i modelli constano di un nucleo di elio contenente il 90% della massa totale e di un inviluppo idrogenico. Essi possono interpretarsi come i resti di stelle che abbiano perso una frazione di massa considerevole in fasi evolutive precedenti, o all'innesco violento dell'elio al centro.     

Космическое черенковское излучение

, . N/E, E _r, (E _r)=1. , (, ) . .     

Гидромагнитное Излучение Межпланетной Плазмы

0–2 ( ). . . .     

Narrow-band photometry of Wolf-Rayet stars and planetary nebulae

We present observational data in the (16)(9)(25)-photometric system for 11 Wolf-Rayet stars and 7 planetary nebulae. The results show anomalous (16)(9)-indices for these emission objects. Six W-R stars show possible variations in the strength of the HeII line at 6560 Å, perhaps none in the strength of the HeI line at 10830 Å. In spite of these misconstrued (16) and (9)-indices, most WC stars are separated from WN stars in the (16)(9)-array; and PN, in this diagram lie far apart from all kind of stellar objects. The results, yielded by the (25)-index, indicate that the HeI and HeII lines at 10830 Å and 10124 Å, respectively, are probably well suited for photometric examination in W-R stars, PN and other peculiar objects.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

A search for discrete gamma-ray sources of energy greater than 2×1012 eV

The results of the observations to search gamma-ray sources with the energy greater than 2×10¹² eV, which were made in Crimean Astrophysical Observatory during the years 1969–73 are presented. A technique of the detection of the EAS Cerenkov flashes was used.The quality of the data obtained is analysed. The criteria for the selection of the data free from meteorological variations are considered.It was shown that two objects, namely, Cyg X-3 and Cas -1, may be the sources of high-energy gamma quanta. It is probable that the object with the coordinates =05^h15^m, =+1° is the source of gamma-rays as well. An unidentified object Cas -1 is variable: gamma-ray flux was observed twice — in Sepember–October 1971 and in December 1972. It is possible that the flux from Cyg X-3 has a period of 4.8 hr.

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I I , I I , - >2.10¹² . I . I , I I, I ., - -1 Cyg -3- -I . , =0515 ·=+1° -.I -1 I: I J I- - 1971 1972 . Cyg -3, , - T=4.8 .

     

The Abundance of QSOs in Various Cold Dark Matter Models

Based on the statistics of the peaks in the random Gaussian field, we put forward a method to model the evolution of quasars, which are assumed to be a phenomenon of the early stages for some massive galaxies. Our calculations show that the cold-hot mixed dark matter model with _h = 0.3 cannot match the observed quasar abundance at redshift z = 4.5, and other prevailing CDM models, such as the mixed dark matter model with _h = 0.2, the tilted CDM models with n = 0.7 or 0.8, and the flat CDM models with = 0.6 or 0.7, are compatible with the observation of the abundance of QSOs on the range of z = 2-5.     

Evidence for a low-density inflationary universe?

The inflationary unvierse model predicts the density parameter ₀ to be 1.0 with the cosmological constant ₀ usually taken to be zero, whereas observational estimates give ₀0.2 and ₀10^-57 cm^–2. It was found, however, that the observed variation of angular diameter with redshift for extragalactic radio sources could be interpreted in terms of a low density universe with linear size evolution of the sources for either an inflationary model with 0 or an open model with =0.     

Periodic orbits of stars in axisymmetrical stellar systems

Periodic orbits of stars in axisymmetrical nearly spherical stellar systems have been investigated. Generating orbits have been found among periodic ones relating to the spherically-symmetrical field. The linear approximation appears to be insufficient for constructing periodic trajectories. Possible variants of the generating periodic solutions have been found, which give rise to disturbed periodic orbits in the second approximation.

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, . - . , . , .

     

Абсолютная система высот в краевой зоне луны по наблениям покрытий звэзд

. , .     

Does the gravitational “constant” increase?

The possibility that the gravitational coupling constantG is an increasing function of the cosmic timet is discussed.In Section 1 the Maximal Power Hypothesis (MPH) stating that no power in Nature can exceed the upper boundc ⁵/G (Gunn's luminosity) is advocated.In Sections 2, 3, and 4 the MPH is employed on the cosmological scale to support the idea of an increasingG. In Section 2 the increasingG is obtained by two assumptions - the MPH and the energy conservation law - and by nothing else.In Section 3 the increasingG follows naturally from the MPH in the Einstein-Cartan theory of gravity. The arguments proposed in Sections 2 and 3 lead todG(t)/dt > 0 but cannot specify the form ofG(t). In Section 4 the MPH is applied to the energy of the vacuum and leads to a relation betweenG and the cosmological term,G S ³, valid in a matter-dominated universe (S =S(t) is the expansion factor). This relation plus the time-dependence law (suggested by many authors) t ² = constant, plustH > 2/3 (suggested by observations on the age of globular clusters;H is the Hubble parameter) implies an increasingG. One finds also GU, whereU is the mass density of the universe, in agreement with other studies.     

On the stability of small quasiperiodic motions in the hamiltonian systems

Orbital stability of quasiperiodic motions in the many dimensional autonomic hamiltonian systems is considered. Studied motions are supposed to be not far from equilibrium, the number of their basic frequencies may be not equal to the number of degrees of freedom, and the procedure of their construction is supposed to be converged. The stability problem is solved in the strict nonlinear mode.Obtained results are used in the stability investigation of small plane motions near the lagrangian solutions of the three-dimensional circular restricted three-body problem. The values of parameters for which the plane motions are unstable have been found.

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. , , . . , . , .

     

Классикаци дбиижэхий в обобщэхной плоцкой задачэ трех неподБижнΨη цэнтпов

, -, , .

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On the classification of motion in the generalized two-dimensional problem of three fixed centres

A qualitative analysis and classification of forms of motion in the problem under consideration have been carried out using a method (applicable to any case of integrability) due to Liouville. All the forms of the two-dimensional motions for any masses (negative and complex as well) at fixed centres corresponding to the real potential have been considered.

     

Magnetic reconnection in high-temperature plasma of solar flares

Quasi-steady high-temperature current sheets are an energy source during the main or hot phase of solar flares. Such sheets are shown to be stabilized with respect to the tearing instability by a small transverse component of magnetic field existing in the sheets.     

Sur les solutions Lagrangiennes et euleriennes du probleme generalise des trois corps en axes absolus

Résumé Le présent travail est une continuation d'un autre, publié plus tôt (Doubochine, 1970). On montre ici, que les propriétés des mouvements Lagrangiens et Euleriens établies en mécanique céleste classique sont vraies aussi dans les cas plus généraux, envisagés dans le travail indiqué. On montre de plus, que les trajectoires des points en ces mouvements en axes absolus sont les spirales infinies s'enroulant sur les surfaces des cylindres curvilignes infinis.

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-- , (, 1970). , , , , , , , . , , , , .