The stability parameters of three-dimensional periodic three-body orbits

Formulae containing the elements of the variational matrix are obtained which determine the linear isoenergetic stability parameters of three-dimensional periodic orbits of the general three-boy problem. This requires the numerical integration of the variational equations but produces the stability parameters with the effective accuracy of the numerical integration. The conditions for stability, criticality, and bifurcations are briefly examined and the stability determination procedure is tested in the determination of some three-dimensional periodic orbits of low inclination bifurcating from vertical-critical coplanar orbits.     

Combustion as the cause of comet P/Halley's activity

The totality of the results obtained in the VEGA, GIOTTO and SUISEI projects does not lend itself to interpretation within the old sublimation models of comet activity considering solar radiation as the sole source of energy. Among them are the systematic excess of the velocity and temperature of the gas escaping from the nucleus over the theoretical values, the outflow being concentrated in several ( ~ 12–15) narrow ( ~ 300 m in size at the nucleus) hypersonic jets carrying very large amounts of remarkably fine CHON dust and located along continuous lines on the nuclear surface, intense release from the nucleus or very close to it (2 × 10³km) of CO (Q _Co/Q _{H2 O} = 0.05–0.2) with a smaller amount of CO₂ (Q _{CO 2}/ Q _{H2 O} 0.015), large near-nucleus abundances of C, C⁺ (Q _C/Q _CO 0.29), etc.The new observations, together with some earlier data still poorly understood (e.g. the appearance in the coma of large amounts of C₃) can be accounted for by assuming the cometary ices to contain, apart from hydrocarbons, nitrogen-containing compounds, etc. also of free oxygen ( ~ 15 wt.%). Under these conditions, burning should occur in the products of sublimation under deficiency of oxidizer accompanied by the production of soot, smoke, etc. The burning should propagate under the surface crust and localize primarily at a few sites.The presence of oxygen in cometary ices follows from a new eruption theory assuming the minor bodies of the Solar System to have formed in explosions of the massive ice envelopes saturated by electrolysis products on distant moonlike bodies of the type of Ganymede and Callisto.     

A spectroscopic study of the microorganism model of interstellar grains

The microorganism model of interstellar grains is investigated by spectroscopy from the infrared (IR), visible to the ultraviolet (UV) wave regions.E. coli, yeast and spores ofBacillus subtilis exhibit absorption bands at =3.1 and 9.7 m; they also exhibit several absorptions at 68 m which are in agreement with the observed IS extinction curves.To obtain the extinction curves in the visible and UV regions, dry films of microorganism are prepared on a MgF₂ plate or synthesized quartz plate and their spectra measured. In the wavelength region 190400 nm, conventional spectrophotometers are adopted for the measurement. The extinction curve of the film ofE. coli is similar to the observed IS curve.For the wave-range 100<<400 nm, a vacuum UV spectrometer is adopted to avoid absorptions due to O₂ in the atmosphere. The extinction spectra by this method are in agreement with the result obtained by the conventional method where comparison is possible. The extinction curves ofE. coli and yeast are such that they incrase towards the short wavelength and exhibit a peak at -190 nm, which is different from the well-known IS peak at =220 nm. It remains to be seen whether interstellar low temperatures (1040 K) can shift the peak position in the extinction curve of biochemical materials.     

On the existence of cosmological evolutionary effects

Parameters of the distant galaxy clusters of 3C295 (z=0.46) and Cl 0024+1654 (z=0.39) are compared with the predictions made using galaxies of the local clusters Coma (z=0.023) and DC 0329–52 (z=0.057) taking theK-effect into account. The distributions of colour and morphological type, and the amplitudesF ⁺/F^– of the ₀ 4000 discontinuity are examined and no evidence for evolution of the galaxies and the clusters can be seen.     

Types of rural out-migration in Turkey

An analysis of changes in migration patterns since World War II between inner Anatolia and eastern Anatolia in Turkey is presented. Four periods are distinguished, the exploratory period until 1950, seasonal migration until 1960, mass migration up to the present, and marriage migration from 1975 to the present. The linkages between previous and potential migrants are noted. (SUMMARY IN ENG)     

Hydrodynamical models of type II supernovae

A series of hydrodynamical models of type-II supernova outbursts (SNII) has been calculated. Approximate relations connecting the total outburst energy ε, the mass of envelope ejectedM, the presupernova radiusR, and the amount of ionizing quanta radiated by the supernovaeN _H with such values as the duration of the light curve plateau Δt, and absolute magnitude in the wavelength bandV and photospheric velocityU _PH observed near the middle of the plateau have been established. Advantage has been taken of the relations to obtain a preliminary evaluation for the characteristics of the average SN II: ε=7×10⁵⁰ erg,M=6M _⊙,R=500R _⊙,N _H=2×10⁵⁸. The SNIIs with plateau-like light curves seem to be accounted for by thermonuclear explosions of degenerate cores of red giant stars and result in a total disruption of the star without any stellar remnant. To the contrary, SNIIs with linear light curves have substantially different properties (in particular, they throw considerably less massive envelopes off). These SNII must signify the birth of collapsed objects—neutron stars (pulsars) or black holes.     

Observation of chromospheric evaporation during the solar maximum mission

A sample of flares detected in 1980 with the Bent Crystal Spectrometer and the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission satellite has been analysed to study the upward motions of part of the soft X-ray emitting plasma. These motions are inferred from the presence of secondary blue-shifted lines in the Ca XIX and Fe XXV spectral regions during the impulsive phase of disk flares. Limb flares do not show such blue-shifted lines indicating that the direction of the plasma motion is mainly radial and outward. The temporal association of these upward motions with the rise of the thermal phase and with the impulsive hard X-ray burst, as well as considerations of the plasma energetics, favour the interpretation of this phenomenon in terms of chromospheric evaporation. The two measureable parameters of the evaporating plasma, emission measure and velocity, depend on parameters related to the energy deposition and to the thermal phase. The evaporation velocity is found to be correlated with the spectral index of the hard X-ray flux and with the rise time of the thermal emission measure of the coronal plasma. The emission measure of the rising plasma is found to be correlated with the total energy deposited by the fast electrons in the chromosphere by collisions during the impulsive phase and with the maximum emission measure of the coronal plasma.     

Preliminary observations of solar radio sources with the Culgoora radioheliograph operating at four frequencies

The Culgoora radioheliograph has been modified for observing at 327.4 MHz, which is in addition to the three frequencies (43.25, 80, and 160 MHz) previously available. At the new frequency the array beamwidth is 56, which represents the highest resolution yet available for metre-wavelength solar mapping.At 327.4 MHz the sources of radio emission are mainly in the lowest layers of the corona. Some preliminary four-frequency observations have been made of type I storms. It is found that the source size generally decreases with increasing observing frequency. This result confirms earlier suggestions that the sources of both type I and type III emission are contained in structures whose boundaries diverge outwards in the corona.     

Structural analysis of the gravity field over the American-Antarctic Ridge

This paper discusses the structure of the American-Antarctic Ridge based on analysis of the gravity field. Analysis of the gravity field in different reductions and its transforms allowed the revelation of zonal, regional, and local specific features in the field’s structure and their correlation with contemporary notions on the tectonic zoning of the American-Antarctic Ridge and adjacent regions. The lineament structures of the field allowed locating the areas of spreading zones and principal transform and fracture zones. Comparison between the location of these structural features and the interpretation results of shipboard magnetic measurements confirmed the reliability of the received data. Results of the performed investigations presented in the form of structural schemes are a basis for constructing a model of the tectonosphere under the American-Antarctic Ridge.     

Silica phase transformations in the petroliferous sequences

The joint evolution of organic matter and silica in petroliferous sequences is considered in the terms of the laws of transformation of dispersion systems. The dispersion systems are transformed under conditions of low-temperature solid-phase processes accompanied by the silica phase transition and dehydration that favors the evolution of organic matter.