Generalized Problem of Two Fixed Centers or the Darboux-Gredeaks Problem

A brief review of publications on the problem of two fixed centers is given, including its generalizations and astronomical applications. A comparison of the Darboux potential with that of Eve Gredeaks is made. An account of the basic points of development of modern high-precision theories of the motion of planetary satellites, based on the Gredeaks’ intermediate orbit, is given.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 194–200.Original Russian Text Copyright © 2005 by Lukyanov, Emeljanov, Shirmin.Dedicated to the memory of Professor Evgenii Petrovich Aksenov     

A model of radiation conditions during spacecraft flights in the interplanetary space and in the Earth's magnetosphere.

Based on the available measurement data, simulations of radiation conditions during spacecraft flights in the interplanetary space and in the Earth's and Jupiter's radiation belts has been carried out. The > or = 10 MeV and > or = 30 MeV solar flare proton fluence forecast has been proposed for Cycle 22. Radiation conditions due to both magnetospheric electrons and protons and to solar flare protons, magnetic rigidity cutoff being taken into account, have been evaluated on spacecraft trajectories in the Earth's and Jupiter's magnetospheres.     

1E 1740.7-2942 revisited: Confirmation of its identification with the core of a double sided radio jet structure

After more than two years of successful in-orbit operations, the γ-ray coded aperture SIGMA telescope has accumulated 800 hours of live-time observations of the Galactic Center region, including the remarkable hard source identified with the X-ray source 1E 1740.7–2942. The long-term behavior of the soft γ-ray emission of 1E 1740.7–2942, as determined from the SIGMA survey, supplemented with previously available soft γ-ray data, leads to its identification with a singular radio source, which consists of a double sided radio jet emanating from a compact variable core whose variability is correlated with that of the soft γ-ray source. The compact radio core, which lies well inside the improved soft γ-ray (40–150 keV) error circle (27″ radius) derived from the high-resolution SIGMA survey, is also inside the ROSAT and TTM error circle derived respectively in the soft and hard X-ray bands.     

Microwave spectrum analysis as solar energy release diagnostics

The possibilities of using spectrographic observations of microwave radio emission as a solar flare plasma diagnostic are discussed. The spectral fine structure of the emission is interpreted in the context of plasma emission mechanisms. The balance equations for particles and plasma turbulence together with the transfer equations for electromagnetic waves in a plasma are solved for a model containing a diverging magnetic loop. As a result of the analysis of the blip-type spectral feature, the structure of energy release region and the unperturbed plasma concentration in the preflare loop are evaluated. The number of accelerated electrons and the intensity of the plasma turbulence in the source region are estimated using the properties of the weak continuum emission following the blip. Based on the degree of circular polarization of both the narrow band and the continuum emission, estimates for the external magnetic field strength and the angular width of the radiating plasma turbulence have been obtained.     

Balloon-borne far-infrared spectrophotometry of the galactic center region

Far-infrared observations of the Galactic Center have been carried through with the MPE Im balloon-borne telescope “Golden Dragon”. The measurements are composed of photometric scanning (33–95 μm) of the inner 4′×4′ and low resolution spectroscopy (δ^ν = 10 cm^?1) of the center and of a position approximately 1.5′ to the north. A Mars spectrum has been obtained for calibration. The spatial resolution of the photometry map is increased using the Maximum Entropy Method and the resulting map is compared to other observations in the same and other spectral regions. A clear asymmetry in the ring-like structure around the center indicates the presence of noncircular motions. The shape of the spectra is fairly smooth with at least no prominent dust features. A simple modelling shows a drastic increase of column density within 2 pc from the center and a modest drop over the next 3 pc to the north.     

Merging Landsat and spaceborne radar data over Tunisia

Synthetic Aperture Radar data were acquired over Tunisia by Seasat in Aug. 1978 and by SIR-A in Nov. 1981. The radar images are contrasted to the Landsat scenes overlapping the same area. The Landsat images were taken in Aug. 1978 and in Sept. 1981. In this study, subareas of the SIR-A and MSS images are registered to the corresponding Seasat data (1313 lines by 1970 samples). The test site is located East of Kairouan, Tunisia. It is a low relief area with subdesertic climatic conditions. This region was selected for it has been surveyed by both Seasat and SIR-A providing perpendicular radar illumination directions. The multispectral and multitemporal coregistered data set enables comparisons between the systems (radar versus MSS, and Seasat versus SIR-A), and change detection in the desertification processes and on the surface of the playas.     

Observed and model N(h) profiles for the Bulgarian region

In this paper, combined bottom- and topside ionospheric N(h)-profiles are presented for the Bulgarian region. The profiles were constructed using ground (ionospheric observatories Sofia and Michurin) and satellite (Interkosmos-19) observations /1/.The observatories make quarter-hourly observations; in order to connect bottom and upper parts of the N(h) profile, we selected satellite orbits passing rather near to the observatory (zenith distance lsss than 100 km). Thus the time difference between ground station and satellite measurement was never more than 7.5 min.     

Eutectic solidification of Al-Cu alloys influenced by convection

Directional solidification of eutectic Al-Cu alloys has been studied to demonstrate the influence of both impurity concentration and convective conditions. The λ/R relations show that higher iron concentration and intensive stirring coarsen the microstructure. The formation and growth of new iron-containing phases at the solidification front restrict impurity influence. Kinetic data follow a dependence λ.Rⁿ=const with n-value close to 0,5.     

Sporadic emission of ultra high energy gamma rays from crab pulsar

In a further study of sporadic emission from pulsars we find evidence for short lived intense emission from the Crab pulsar.     

Properties of electrophoretic fractions of human embryonic kidney cells separated on Space Shuttle flight STS-8.

Suspensions of cultured primary human embryonic kidney cells were subjected to continuous flow electrophoresis on Space Shuttle flight STS-8. The objectives of the experiments were to obtain electrophoretically separated fractions of the original cell populations and to test these fractions for the amount and kind of urokinase (a kidney plasminogen activator that is used medically for digesting blood clots), the morphologies of cells in the individual fractions, and their cellular electrophoretic mobilities after separation and subsequent proliferation. Individual fractions were successfully cultured after return from orbit, and they were found to differ substantially from one another and from the starting sample with respect to all of these properties.