Lithological-stratigraphic characteristics of the Aptian-Cenomanian sediments of the Abkhazian zone of the Western Caucasus

For the first time, a complex lithological-stratigraphic and facial study of the Aptian-Cenomanian sediments of the Abkhazian zone of the Northwestern Caucasus was carried in sections of the Mzymta and Khipsta river valleys. As a result, the areas of distribution of potential oil-source rocks in these sediments, which correspond to the events of the OAE-1 and OAE-2 global paleoecological crises, oil reservoir rocks and rocks-caps were defined.     

The He I 10830 Å Line as an Indicator of Solar Activity

The behavior of the He I 10830 Å infrared triplet parameters in active and quiet solar regions was traced from 1976 until 2000. We analyze the correlation between the central depth of the main He I line component and other solar activity indices: the Wolf number, the radiation flux at a frequency of 2800 MHz, the mean number of flares in sunspot groups, and the mean solar magnetic field. We show that the strong correlation between the He I 10830 Å line depth and the phase of the 11-year solar cycle allows this depth to be effectively used as a new solar activity index both on long time scales (years) and on times scales of the order of a month or even days. The suggested new activity index is shown to have advantages over the universally accepted indices. The depth of the He I 10830 Å line in quiet regions was found to increase from the phase of minimum solar activity to the phase of maximum by a factor of about 2. In active regions, this increase is less than 30%. The differences between the cyclic variations of the chromospheric He I 10830 Å line radiation in active and quiet structures on the solar disk are indicative of the probable differences in the nature of cyclicity and its manifestations in magnetic fields of different spatial scales. The background magnetic fields appear to vary during the solar cycle more strongly than do the local fields associated with sunspots, faculae, and activity complexes. We suggest using regular observations in the He I 10830 Å line to predict solar activity.     

The Area of Cold Traps on the Lunar Surface

We numerically calculate the probability and area of permanent shadowing as a function of the selenographic latitude as well as the total area of the permanently shadowed surface for various hierarchical models of the lunar surface. The permanently shadowed area is shown to rapidly increase with increasing number of hierarchical surface levels. For a two-level model of the lunar relief, where the surface of craters is complicated by a random small-scale relief with a Gaussian distribution of heights and slopes, the area of the doubly shadowed regions of the lunar surface is approximately an order of magnitude smaller than the area of the singly shadowed regions. A comparison of the permanently shadowed area calculated by using averaged statistical relations and data on the actual distribution of craters near the lunar poles shows almost complete agreement.     

Influence of stellar wind on the long-term variability of the Hα emission line. The case of the Herbig Ae-star HD 31648

The results of high-resolution long-term spectral monitoring in the region of the emission Ha line of the Herbig Ae star HD 31648 are reported. The variability in the observed profile is shown to be caused mainly by a change in the parameters of outflowing circumstellar gas over a time scale of about 3 years. __________ Translated from Astrofizika, Vol. 49, No. 1, pp. 81–90 (February 2006).     

Spots and active regions on the emission-line, red dwarf star v 775 her

Quasi-simultaneous photoelectric and spectroscopic observations of the active spotted star V 775 Her have been made for the first time and showed an increase in the equivalent width of the pure emission in the H_a line with a decrease in the star’s brightness. Such an increase was due to an increase in electron density in the active regions and demonstrates a connection between active regions and cool spots. The system’s photometric variability is fully described within the framework of a zonal model. The spotted regions occupy up to 42% of the star’s total surface if the temperature difference between the quiet photosphere and a spot is about 900 K. The ratio of the masses of the components of V 775 Her is estimated for the first time. Translated from Astrofizika, Vol. 43, No. 3, pp. 339-351, July–September, 2000.     

Diagnostics for accretion disks around UX Ori stars based on Balmer, Paschen, and Brackett Lines

We have modeled the H_α, H_β, and H_γ (Balmer series), P₁₄ (Paschen series), and Br_γ (Brackett series) hydrogen lines formed in the inner regions of the accretion disk around the Herbig Ae star UX Ori. Our calculations are based on spectra obtained with the Nordic Optical Telescope (NOT) and the IRTF. We computed a grid of non-LTE models for a radiating area in the accretion disk and determined the basic parameters of the lines using the method of Sobolev. Analyzing the theoretical and observed line profiles, equivalent widths, and luminosities, we have estimated the accretion rate and electron-temperature distribution in the inner parts of the accretion disk. The accretion rate of UX Ori is about $\dot M_a = (3 - 10) \times 10^{ - 9} M_ \odot /yr$ , and the temperature distribution is consistent with the power law T(r)=T(r _*)(r/r _*)^?1/n , where the electron temperature near the stellar surface T(r _*) is 15000–20000 K and the power-law index n≈2–3 is about two to three. The resulting value for $\dot M_a $ eliminates problems connected with the application of magnetospheric accretion models to Herbig Ae/Be stars. Another important conclusion is that, at the estimated accretion rate, the energy release is substantially (about two orders of magnitude) lower than the stellar luminosity. Therefore, the optical radiation of UX Ori accretion disks cannot appreciably contribute to the observed variability of these stars, which must be determined mainly by variability in the circumstellar extinction.     

The Problem of Reducing the Diffuse Pollution of Water Bodies and Improving the Efficiency of Water Protection Programs

Water Resources - Regularities in the formation of diffuse pollution of water bodies are discussed as their understanding is required for the development of an adequate water-protection strategy....