The quantitative interpretation of solar X-ray images

We examine the interpretation of plasma parameters derived by quantitative analysis of solar X-ray photographs obtained through broad band filters. We find some of the recent criticisms of the filter ratio method to be unfounded. Using active region and quiet Sun emission measures derived mostly from spectroscopic observations we find that effective emission measures and temperatures derived from S-054 data by filter ratio analysis are within better than 20% of the total emission measure and average temperature, respectively. The uncertainties associated with filtered flux determination are found to produce an error of about 10% in the derived effective temperature. We thus conclusively demonstrate that parameters derived from S-054 data by filter ratio analysis are representative of the observed active region and quiet Sun material.     

The modified Lagrangian equations of general-relativistic hydrodynamics for a nonideal fluid

The general-relativistic equations of hydrodynamics for a nonideal fluid are derived in the modified Lagrangian form. Together with the zeroth and first moment equations of radiative transfer derived by Morita and Kaneko (1986), the equations provide a complete set of the modified Lagrangian equations of radiation hydrodynamics. The equations of hydrodynamics are specialized for a thermally conducting, Newtonian viscous fluid in the modified Lagrangian form, which are the generalization of the specialrelativistic equations of hydrodynamics derived by Greenberg (1975).     

Investigation of the galaxy distribution in a field at the boundary between Virgo and Serpens Caput

The number density distributions for further 13 cluster of galaxies are derived by counting galaxies on the red Palomar Sky Survey prints. For these clusters the radial number density distributions and the radial cumulative galaxy distribution are derived.     

Escape or retention in the three-body problem

Sufficient conditions for escape and for retention in the three-body problem are derived which, for escape, are more stringent than those previously derived and, for retention, avoid the difficulty of containing the inverse of the mass of the escaping particle.     

Dynamical equations of a magnetofluid universe

Dynamical equations of magnetofluid are derived for Robertson-Walker line element. We recover the results of perfect fluid in a special case when the magnetic field is made to vanish. Certain conditions are derived to show that the magnetofluid universe is open or closed.     

A new class of relativistic perfect fluid cylinders with expansion proportional to shear scalar

A new class of relativistic perfect fluid cylinders with expansion proportional to shear scalar have been derived by considering the Einstein-Rosen metric. It is shown that the solutions obtained by other workers do not satisfy the isotropy conditions and therefore are erroneous. The solutions derived in this article are analyzed kinematically.     

Structural Investigations in the Central Part of the Coma Cluster on the Base of Equidensity Diagrams. I.

On the base of a photographic plate in system V, which was taken with the 134/200/400 cm Schmidt camera of the Karl-Schwarzschild-Observatorium Tautenburg maximal diameters of galaxies in the centre of the Coma cluster are determined by photographic equidensitometry. An other system of diameters is determined for medium densities of the objects. The results are compared with ROOD and BAUM'S who derived the diameters by visual measurements on plates taken with the 5-metre telescope of the Hale Observatories. Both statistics contain galaxies up to 19^m. They are complete up to 17^m.5. It is pointed out that the Tautenburg diameters are in the mean 3 times larger than those derived by ROOD and BAUM. Diameter-magnitude diagrams and ellipticities of the objects are derived, further photometric corrections for tilted objects. For describing the general structure of the cluster diameter functions are derived instead of magnitude functions. The accuracy of a brightness determination by the equidensity method from the diameter-magnitude diagrams is nearly twice better than according to ROOD and BAUM.     

Theoretical Signature of Solar Meridional Flow in Global Seismic Data

Approximate expressions are derived for the perturbations in solar p- and f-mode oscillation eigenfunctions, due to large-scale, meridional flows which are symmetric about the equator. The essential signature of the perturbed eigenfunctions in global helioseismic data is derived and the prospects for detecting meridional flow using global seismic techniques are discussed.     

Magnetohydrodynamical model of pulsar rotation. Exact periodic solutions

A rotaing rigid body with elipsoidal cavity filled with magnetic fluid is considered as a pulsar model. Dynamical equations for the pulsar model are derived and investigated, certain integrable cases are indicated. Three–parameter sets of periodic solution integrable in terms of elliptic functions of the time variable are obtained. A formula is derived for the period of rotation and magneto–rotational oscillations of the pulsar.     

Perturbations in satellite orbits due to variations in rotation of the central body

Variations in satellite orbital elements are derived due to perturbations in the external gravitational field of the central body caused by mass deformations of the body occurring from variations in its rotation; the central body is assumed to be perfectly elastic. General theory derived is applied to the actual Earth, as an example; possible resonances are discussed.     

对脉冲星发射宇宙线能量的估计

S.Karakula等人根据Ostriker等人的脉冲星产生的宇宙线能谱依赖脉冲星年龄的理论模型,利用脉冲星发射宇宙线的最大能量:     

Analytical method for the effects of the asteroid belt on planetary orbits

Analytic expressions are derived for the perturbation of planetary orbits due to a thick constant density asteroid belt. The derivations include extensions and adaptations of Plakhov's analytic expressions for the perturbations in five of the orbital elements for closed orbits around Saturn's rings. The equations of Plakhov are modified to include the effect of ring thickness and additional equations are derived for the perturbations in the sixth orbital element, the mean anomaly. The gravitational potential and orbital perturbations are derived for the asteroid belt with and without thickness, and for a hoop approximation to the belt. The procedures are also applicable to Saturn's rings and the newly discovered rings of Uranus.The effects of the asteroid belt thickness on the gravitational potential coefficients and the orbital motions are demonstrated. Comparisons between the Mars orbital perturbations obtained using the analytic expressions and those obtained using numerical integration are discussed. The effects of the asteroid belt on the Earth based ranging to Mars are also demonstrated.     

The transfer of polarized radiation in spectral lines: Formalism and solutions in simple cases

A general treatment of the transfer of polarized radiation in spectral lines assuming a Rayleigh phase function and a general law of frequency redistribution is derived. It is shown how nine families of coupled integral equations for the moments of the radiation field arise which are necessary to fully describe the state of polarization of the emergent radiation from a plane-parallel, semi-infinite atmosphere. The special case of angle independent redistribution functions is derived from the general formalism, and it is shown how the nine families of integral equations reduce to the six linearly independent integral equations derived by Collins (1972). To serve as a test of the formulation, solutions for isothermal atmospheres are given.     

The orbits of open clusters in the Galaxy

We present and analyse the kinematics and orbits for a sample of 488 open clusters (OCs) in the Galaxy. The velocity ellipsoid for our present sample is derived as  (σ _U , σ _V , σ _W ) = (28.7, 15.8, 11.0) km s⁻¹  which represents a young thin-disc population. We also confirm that the velocity dispersions increase with the age of a cluster subsample. The orbits of OCs are calculated with three Galactic gravitational potential models. The errors of orbital parameters are also calculated considering the intrinsic variation of the orbital parameters and the effects of observational uncertainties. The observational uncertainties dominate the errors of derived orbital parameters. The vertical motions of clusters calculated using different Galactic disc models are rather different. The observed radial metallicity gradient of clusters is derived with a slope of   b =−0.070 ± 0.011   dex kpc⁻¹. The radial metallicity gradient of clusters based on their apogalactic distances is also derived with a slope of   b =−0.082 ± 0.014   dex kpc⁻¹. The distribution of derived orbital eccentricities for OCs is very similar to that derived for the field population of dwarfs and giants in the thin disc.     

大气激发和观测极移之间的转换变化分析

本文采用１９８４—１９９２年期间日本气象厅（ＪＡＭ）推算出的大气激发函数序列（χ１，χ２），和美国喷气推进实验室（ＪＰＬ）提供的Ｓｐａｃｅ９３极坐标序列经过反卷积而推出的测地激发函数（ψ１，ψ２）进行了比较。同时也比较了极移（ｘ，ｙ）和从大气激发序列归算出（经过卷积）激发极移（ｍ１，ｍ２）。     

Contribution of Mars Odyssey GRS at Central Elysium Planitia

The neutron signals measured by the Neutron Spectrometer on board the Mars Odyssey satellite are analyzed at Central Elysium Planitia. The neutron currents have variations associated with the boundaries of geological units in all three energy ranges: thermal, epithermal and fast neutron. Geochemical constraints can be derived from the neutron data using macroscopic absorption cross sections. This variable measures the ability of a material to absorb neutrons, giving clues of its chemical composition. The neutron derived chemical constraints are compared with the elemental abundances measured by the Gamma Subsystem, also on board Mars Odyssey. Differences between the two datasets are interpreted to reflect heterogeneities of probed surfaces. The knowledge already derived from other observations and a detailed examination of the GRS datasets are used to determine a general overview of the geology of the region and possible mechanisms of emplacement. The particular role played by chlorine in this scheme is emphasized.     

Mid-ultraviolet and optical photometry of helium stars

Mid-ultraviolet and optical photometric analysis of helium stars are presented. A linear relation exists between the effective temperature derived from model atmospheres and (1965-V)₀ index. The effective temperatures derived from (1965-V)₀ index are somewhat higher than that of MK spectral type estimates especially for late B-type helium objects.     

A thermodynamic origin of a universal mass-angular momentum relationship

The distribution functions for the total linear and angular momentum ofN particles selected from an equilibrium gas are derived. The most probable momentum increases withN. If the particles of an astronomical system are assumed to come from an original cosmic gas, universal mass-versus-momentum relations can be derived. The derived mass-versus-angular momentum relation is similar but not identical to that which has been reported. The derived relationship applies to the initial conditions and evolutionary effects may account for the difference between this prediction and the observed relationship.     

Elemental abundance analyses with DAO spectrograms – XIX. The superficially normal B starsζ Draconis, ε Lyrae, 8 Cygni and 22 Cygni

Elemental abundances of the superficially normal early and middle B starsζ Dra, ε Lyr, 8 Cyg and 22 Cyg are derived, consistent with previous studies in this series, using spectrograms obtained with Reticon and CCD detectors. Almost all of the derived metal abundances are found to be solar within the errors of the analysis. However, the He/H ratios are slightly greater than solar.     

Quasielectrostatic whistler-mode propagation

An approximate formula is derived for the refractive index of a whistler-mode wave propagating in a hot anisotropic plasma with wave normal angle close to the resonance cone angle (θ_R). Approximations used during the derivation are generally satisfied for magnetospheric conditions. It is pointed out that the derived formula can be considered to be complementary to the corresponding formula for quasilongitudinal whistler-mode propagation in a hot anisotropic plasma which was derived by Sazhin and Sazhina (1982). The limits of applicability of a cold plasma model when determining the height of generation of saucer emissions and V-shaped hiss are discussed.