Effects of metal abundances on the evolutionary period changes of classical Cepheids

Some peculiarities in the behaviour of a model self-gravitating system described by hydrodynamical equations and isothermal equation of state connected with the presence of thermodynamical fluctuations in real systems were investigated in numerical experiment. The values of density and velocity , , respectively, were computed by numerical code perturbed on each time-step and in each computational cell by random values , for modeling such fluctuations. Perturbed values _i = _i + _i ,v _i = _i + v _i were used to initiate the next step of computations. This procedure is equivalent to an introduction into original hydrodynamical equations of Langevin sources which are random functions. It is shown that these small fluctuations (= v =0,² =v ² = 10^–8) grow many times in marginally-stable state.     

О лагранжевых и зйлеровых решеиях обощенной задачи трех тел

(, 1969). ( ), ( ), , , . , (=), , , .. , . , , - ( ), ( ). , .

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This paper is a continuation and a generalization of one published earlier (Duboshin, 1969): it discusses the problem whether there exist the Lagrangian and the Eulerian solutions of the generalized three-body (material points) problem. Every point in this generalized problem acts on another, one with a force (attractive or repulsive) directed along the straight line passing through these points, and in an arbitrary manner depending on time, mutual distance and its derivatives, the first and the second. Here, generally speaking, the third axiom of dynamics (law of action and reaction) is not presupposed as fulfilled, that is, it is supposed that every two material points interact in a different way.This most general assumption being made, we establish the conditions which must dictate the laws of the interactions, so that the three points can always remain at the apexes of the equilateral triangle (Langrangian solution), or remain always on a straight line (Eulerian solution).The author believes that such general treatment of the three-body problem can be useful for theoretical studies in celestial mechanics and also for practical applications in the study of isolated stellar systems.

     

Несколько замечаний о гамма-излучении и химическом составе квазаров

, - ( , - ) . () .     

МасштаБ и напряженность галактического магнитного поля поданньым пулБсаров

, , 38 B=2.1±1.1 G l _o=99°±24°,b=0° N _e=0.03±0.01 ^–3 Z- (h400 ). , 100–150 .     

Sur le probleme restreint circulaire des trois corps solides

Résumé Il est envisagé dans ce travail un cas particulier du problème des trois corps solides. On suppose qu'un des corps est passif, c'est-à-dire qu'il n'agit pas sur les deux autres. Chaque corps posséde la symétrie axiale, ainsi que la symétrie par rapport à plan, perpendiculaire à cet axe, Au moment initial les plans de la symétrie des corps coinsident avec le plan principal des coordonneés. Alors il est possible de choisir les conditions initiales de sorte que les centres de la symétrie resterons toujours dans le plan principal, chaque corps tournant uniformement autour son axe. Nous nommerons ce problème — le problème restreint plant. Le cas le plus simple est le problème plan circulire, quand le centre d'un des corps actif décrit orbite circulaire authour d'autre corps actif. Ce problème se reduit à l'étude du mouvement du centre d'inértie du corps passif dans le plan principal —plan d'orbite circulaire du corps actif. Nous trouvons les conditions d'existence pour les solutions particulières du ce problème et posons la question de la stabilité des points de libration correspondantes. D'une manière plus détaillée nous envisageons le cas, où toutes les forces actives sont définiérs une par loi unique.

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, . , , , . . , , . . , , . , , . , , . . . , , .

     

Магнитное поле вращающегося оБлака и магнито-ротационные взрывы

, , . . ( I), ( II). I , () . -, . , , (R/R _i)^2/3, R/R _i- . ( II) . , . , , , . , . , , . , , - , , . , , , , . , . . . 1969 .     

Hubble expansion in a euclidean framework

, . . , , . , ,      

Динамические равновесные плазменные конфигуации и физика магнитосферы

, 1-, 2- 3- . , .     

О природе всплесков γ-излучения

- . , - . -.     

Сешение плоской задачиn неподвишньих центров

.

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For a special choice of parameters the plane problem of the motion of a passively gravitating material point in the gravitation field ofn fixed centres is reduced to quadratures.

     

On a possible mechanism responsible for the differential energy spectrum of relativistic electrons and non-linear low-frequency spectra of cosmic radio sources

The paper suggests an explanation of the deviations from the power law which are observed in frequency spectra of discrete radio sources at decametric wavelengths. It has been shown that a possible mechanism of the deviations is a combined effect of the stimulated and spontaneous scattering of relativistic electrons in the turbulent plasma of a source, as well as ionization energy losses thereof. The distribution function of the relativistic electrons, empirically established in an earlier paper (Braudeet al., 1971) has been derived from the kinetic equation. For a number of discrete sources the turbulence energy density and the plasma concentration are deduced with the aid of experimental data on low-frequency radio spectra.

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. , , . , (Braude et al, 1971), . .

     

Оптимальное демпфирование нутационного движения спутников, стаБилизируемых вращением

, . , , . , , -, This article investigates the dynamics of a system for damping the nutating motion of a spin-stabilized satellite. The equations of motion of the satellite-damper system are derived omitting consideration of the influence of external torques. The conditions of stability of the stationary spinning are obtained and the optimal parameters of the satellite and the damper ensuring a maximal rate of damping of the nutation motion are determined.     

Оболочки звездпри сверхкритической светимости

. , , .. . . , (, ) .     

Повевхное магнитосферное течение С силяными разрывами

=qm . . ¶, I . — , ¶, 5. , . : , , . =ah 4. . . , -, ( ). .     

Ускорение релятивистских электронов в плазменных реакторах и нелинейные спектры космических радиоисточников

( , 1977; , 1977). , , , . .     

The ‘naked’ singularity in the scalar-tensor gravitation theory

The complete analysis of possible types of non-relativistic and ultra-relativistic motions in the field of the naked singularity of the STGT is given. The problem of the infall of a monochromatic radiation emitter on the naked singularity is studied. In spite of the absence of a freezing effect in the STGT, the naked singularity is not observable, for the brightness of the falling emitter decreases much faster than in the GTR. Atrr _g , the trajectory of particles and light are quite similar to that of the GTR, and due to this fact the naked singularity is observationally indistinguishable from a black hole.     

О природе квазаров и активных ядер галактик

( — , , ). ( , ) . , .

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, 40 48 MAC (, 1976).     

турбулентноштб в космологии

=qr, I II (Marochniket al., 1975 a, b), . , II; , . , , ye , . . t _g.     

Сопоставление модели карлсона с моделью сплошной среды

, (1962, 1963) . , (1) (2) .     

The λ 747 coronal line at the 1966 eclipse

Observations are presented of emission line resonance polarization in Fe xiii 10747 at the total solar eclipse of 12 November 1966. Useful data, with angular resolution 15, describe three quadrants of the corona from 1.08 R to a maximum of 1.6 R . The direction of the electric vector of observed polarization is perpendicular to the solar limb, to the limits of accuracy of measurement, in at least 74% of all cases. Departures in the other points are consistent with the magnetic depolarization expected from the non-radial fields of streamers. Polarizations observed range from near zero at the limb to 80 % and higher at 1.6 R . Averaged polarization is highest in non-streamer regions, where above 1.2 R it suggests pure radiative excitation of the 10747 line. Below 1.2 R , and in a dense streamer, the polarization is significantly depressed, indicating dominant collisional excitation of the line wherever the electron density exceeds 50 × 10⁶ cm^–3.The National Center for Atmospheric Research is sponsored by the National Science Foundation.