Problems of exploration level of hydrometeorological regime of the Northern Caucasus territory

The main problems of the study of the meteorological regime, climate, hydrology, snow avalanches, mudflows, and glaciers are considered. It is demonstrated that the level of their exploration on the plain territory is sufficient on the whole, however, the mountain territories are poorly studied. The opening of new stations including the automatic ones and the organization of snow-route observations are required. It is necessary to carry out the preparation and publishing of new handbooks on the climate and surface water resources and to create the catalogs of glaciers, snow avalanches, and mudflows on the basis of the modern topographic maps and satellite images.     

Sources,seasonal variability,and trajectories of atmospheric aerosols over central Siberian forest ecosystems

The possibility to obtain reliable data on the chemical and physical characteristics of aerosols and the regularities in the processes of their formation and transportation under the background natural-climatic conditions is a necessary requirement for verification of existing climate models [1, 2].     

Fission and the <Emphasis Type="Italic">r</Emphasis>-process: Competition between neutron-induced and beta-delayed fission

We show that for the discussed scenario of a neutron-star merger in highly neutronized ejecta (Y _e ?0.1), neutron-induced fission plays a major role in the r-process cycling and is the main obstacle to the formation of superheavy elements. At the final stage of the r-process, when the free-neutron density is already too low to maintain rapid nucleosynthesis and only beta-decay and beta-delayed fission take place, the leading role in forming the final abundances of chemical elements passes to delayed fission. The latter ultimately changes the abundances of individual isotopes in the region before the second peak and heavier than lead, which, in particular, affects the determination of the age of the Galaxy.     

On the production of chemical elements beyond the iron peak

Astronomy Letters - We discuss the possibility of elements heavier than iron being produced in the cooling central part of a low-mass supernova remnant in terms of a consistent kinetic model that...     

Jurassic magmatic bodies of mountainous Crimea in the Bodrak River catchment (Southwestern Crimea)

The synthetic (geological and petrochemical) study of Jurassic magmatic bodies in the catchment of the Bodrak River (mountainous Crimea) is conducted. Their structural position and a Middle Jurassic age were determined. The magmatic bodies of mountainous Crimea were compared to those of the Lozovskaya zone. The study considers the geodynamic settings of the Middle Jurassic magmatism in mountainous Crimea.     

Contribution of fission to heavy-element nucleosynthesis in an astrophysical <Emphasis Type="Italic">r</Emphasis>-process

During the formation of heavy elements in the neutron star merger (NSM) scenario with a fairly long duration of the r-process, most of the seed nuclei rapidly burn out at the initial stage. The nucleosynthesis wave rapidly reaches the region of actinoids, where beta-delayed, neutron-induced, and spontaneous fission are the main reaction channels. The fission products of transuranium elements are again drawn into the r-process as new seed nuclei to form the yields of elements with mass numbers A > 100. The contribution from the various types of fission to the formation of heavy and superheavy nuclei is investigated. The proposed r-process model applied to the NSM scenario describes well the observed abundances of chemical elements, which confirms the formation of the main r-process component in the NSM scenario. Simple extrapolations of the spontaneous fission half-lives are shown to be inapplicable for the region of nuclei with N ∼ 184, because the formulas do not reflect the increase in half-life when the shell structure changes as the number of neutrons approaches 184. The formation of superheavy elements in the r-process is possible, but their survival depends to a large extent on how reliable the predictions of nuclear parameters, including the half-lives of the forming nuclei from the island of long-lived isotopes, are. The contributions from various types of fission—neutron-induced, beta-delayed, and spontaneous one—to the formation of heavy elements in the main r-process have been determined.     

Photometry of the spotted flare star by dra during 1985-1991

Spot photometry in theUBV was obtained for the flare star BY Dra during 1985-1991 at the Bulgarian National Astronomical Observatory. Light curves are presented for 1986, 1987, 1988, and 1991. There are significant variations of the amplitudes of the light curves implying changes of the spot distribution. The phases of the light minima are variable, indicating possible latitudinal migration of the spot and differential rotation. Rough estimate of the corresponding latitudinal shear is in the range 3 × 10^–11 –5 × 10^–10 rad s^–1 deg^–1. The photometric behaviour of BY Dra since 1960 shows no compeling evidence for existence of stellar cycles. This is in contradiction with previous studies. During 1985-1991 a total of 38.47 hours of monitoring in theU-filter were obtained. Analysis of the flare activity of BY Dra shows no significant changes from previous studies.     

CH Cygni in the transition to its cool phase

U, B, V-observations, supplemented by spectrophotometric measurements of the symbiotic variable CH Cyg in the years 1982 to 1984 show that the star has reached its blue maximum phase of its recent outburst in the first half of 1984. From end of July, 1984 on the object underwent a considerable drop in brightness and an increase of its colour indices, and which indicates that it was on the way to its cool phase. Also the spectroscopic observations show that the blue continuum still observed at the beginning of July, 1984 has disappeared in October–November, 1984 and the strong absorption features, typical for a M-type giant were re-appearing. A remarkable intensity increase of the emission features, especially those of the Balmer lines, took place within this time interval. The rapid flickering variations of CH Cyg had also reached the culmination amplitude in July, 1984. There seem to be three periodicities present in these flickering variations with cycle lengths of 7.7 min, 21 min, and 60 min. Though these observational findings would be consistent with the M-type blue subdwarf component binary model with mass flow from the M6-III giant to the companion, the genuine binary nature of CH Cyg could not be established beyond doubt.     

The relativistic spherical accretion by black holes

The relativistic spherical accretion onto black holes is considered. It is shown that electron heat conductivity and ion viscosity increase the ion temperature by roughly two orders of magnitude over the electron temperature at Schwarzschild radius. As a result, the knee arise in gamma-radiation spectrum at 10–30 MeV. The role of magnetic field, electron-positron pairs production and generation of absorption lines in spectrum briefly discussed.