The accretion activity of the Ae Herbig star CQ Tau

Results of spectral observations of the isolated Ae Herbig star CQ Tau obtained in 1995–1998 in the H_α line and near the sodium resonance doublet are presented, together with simultaneous photometric monitoring of the star. CQ Tau is a member of the family of young UX Ori stars with nonperiodic Algol-like brightness decreases. The star is surrounded by an accretion disk, in which its emission-line spectrum and part of its absorption-line spectrum are formed. The strong variability of the H_α, D NaI, and HeI 5876 Å lines testifies that the gaseous disk is appreciably inhomogeneous in both the radial and azimuthal directions. This inhomogeneity probably results from uneven feeding by the circumstellar material from the peripheral regions of the circumstellar disk. Over the four years of observations, we observed the star in deep minima three times (ΔV～2). On these nights, an increase in the H_α equivalent width followed the decrease in radiation flux. In the two deepest minima, the normally two-component line profile had only a single component with a nearly symmetrical profile. This behavior of the H_α line is in good agreement with the results of numerical modeling of Algol-like minima and can be used to estimate the parameters of the dust clouds eclipsing the star and inner accretion disk. These estimates suggest that the circumstellar dust clouds can approach very close to the star and be sublimated there.     

Pollution of Sources of Drinking Water Supply of Large Cities with Pharmaceuticals (the Example of Moscow,Russia)

Identification of contaminants, determination of their biological hazard and content in water are important practical tasks while assessing water quality in sources of drinking water supply of large cities. Presented herein is a review regarding pharmaceutical pollution of waters in various countries. Given are original data concerning contamination of water objects—sources of water supply of Moscow with components of pharmaceuticals and metabolites of therapeutic agents. Worked out is a retrieval and calculation technology of assessing hazards of substances. Proposed is the use of “structure-activity” calculation technologies for prediction of side effects of pharmaceuticals and pharmacological activity of other organic xenobiotics not used in medicine. Certain ways of decreasing pharmaceutical pollution are recommended.     

The Character of Evolution of Rock Fracture Processes from Observations of Acoustic Emission and Time Variations in Radon Volumetric Activity

Izvestiya, Physics of the Solid Earth - Laboratory experiments on monitoring the acoustic emission signals and time variations of volumetric activity of radon during uniaxial loading of a granite...     

The Destruction of Small Lunar Craters

Solar System Research - The paper discusses three types of processes of destruction of small lunar craters: (1) destruction by overlapping craters; (2) destruction due to filling with ejecta from...     

Seasonal characteristics of tropical marine boundary layer air measured at the Cape Verde Atmospheric Observatory

Observations of the tropical atmosphere are fundamental to the understanding of global changes in air quality, atmospheric oxidation capacity and climate, yet the tropics are under-populated with long-term measurements. The first three years (October 2006–September 2009) of meteorological, trace gas and particulate data from the global WMO/Global Atmospheric Watch (GAW) Cape Verde Atmospheric Observatory Humberto Duarte Fonseca (CVAO; 16° 51′ N, 24° 52′ W) are presented, along with a characterisation of the origin and pathways of air masses arriving at the station using the NAME dispersion model and simulations of dust deposition using the COSMO-MUSCAT dust model. The observations show a strong influence from Saharan dust in winter with a maximum in super-micron aerosol and particulate iron and aluminium. The dust model results match the magnitude and daily variations of dust events, but in the region of the CVAO underestimate the measured aerosol optical thickness (AOT) because of contributions from other aerosol. The NAME model also captured the dust events, giving confidence in its ability to correctly identify air mass origins and pathways in this region. Dissolution experiments on collected dust samples showed a strong correlation between soluble Fe and Al and measured solubilities were lower at high atmospheric dust concentrations. Fine mode aerosol at the CVAO contains a significant fraction of non-sea salt components including dicarboxylic acids, methanesulfonic acid and aliphatic amines, all believed to be of oceanic origin. A marine influence is also apparent in the year-round presence of iodine and bromine monoxide (IO and BrO), with IO suggested to be confined mainly to the surface few hundred metres but BrO well mixed in the boundary layer. Enhanced CO₂ and CH₄ and depleted oxygen concentrations are markers for air-sea exchange over the nearby northwest African coastal upwelling area. Long-range transport results in generally higher levels of O₃ and anthropogenic non-methane hydrocarbons (NMHC) in air originating from North America. Ozone/CO ratios were highest (up to 0.42) in relatively fresh European air masses. In air heavily influenced by Saharan dust the O₃/CO ratio was as low as 0.13, possibly indicating O₃ uptake to dust. Nitrogen oxides (NO_x and NO_y) show generally higher concentrations in winter when air mass origins are predominantly from Africa. High photochemical activity at the site is shown by maximum spring/summer concentrations of OH and HO₂ of 9?×?10⁶ molecule cm^?3 and 6?×?10⁸ molecule cm^?3, respectively. After the primary photolysis source, the most important controls on the HO_x budget in this region are IO and BrO chemistry, the abundance of HCHO, and uptake of HO_x to aerosol.     

Eclogitization of basites in early proterozoic shear zones in the area of the village of Gridino, western Belomorie

The considered part of ductile shear zones, which are widespread in the area of the village of Gridino in the central part of the Belomorian Mobile Belt, is accompanied by the high-temperature eclogitization of basites. The paper reports examples of eclogitization in rocks of various age, mostly in rocks of the Early Proterozoic lherzolite-gabbronorite and coronite gabbro complexes. The degrees of structural and mineralogical transformations in unequally deformed bodies of gabbronorites and olivine gabbronorites of the lherzolite-gabbronorite complex are correlated with the degrees of deformations of these rocks and their fluid recycling. The relatively weakly deformed rocks have massive and apomagmatic textures with garnet and omphacite reaction rims at boundaries between grains of magmatic plagioclase and pyroxenes. These rims are typical of the domainal equilibrium stage, which is an intermediate eclogitization stage between a magmatic rock and completely equilibrated eclogite. The enhancement of rock deformation results in the development of equilibrium eclogite with anisotropic metamorphic textures and structures. Textural transformations simultaneous with intense deformations are manifested involved the recrystallization of magmatic minerals and the development of linear fine-grained mineral aggregates of the Pl-Opx-Grt-Omp eclogite mineral assemblage and the systematically oriented growth of much larger mineral neoblasts in amphibole eclogite assemblages.     

Sequence-stratigraphic analysis of the Aptian deposits in the valley of the Mzymta River

In this work, based on the example of a well drilled in the valley of the Mzymta River (Northwest Caucasus) the possibilities of the sequence-stratigraphic method are demonstrated for the first time. This method allows us to clarify the natures of numerous repetitions in the same interval of the geological sequence (modern, ancient landslide or syn-sedimentary-landslide, and tectonic or eustatic). In addition, the geochemical characteristics of bituminous sediments are given. The sequence that was studied in the well shows the complex polygenetic evolution of sediments since Aptian time and the oceanic anoxic event-1.     

Circumstellar Properties of the Herbig Be Star HD 259431. I. Signatures of Magnetospheric Accretion

Astrophysics - Results are presented from a spectroscopic study of the Ae/Be Herbig star HD 259431 conducted from 2010 to 2019 using high-resolution spectrographs at: (a) the Crimean Astrophysical...     

The stellar wind as a key to the understanding of the spectral activity of IN Com

We present long-term spectral observations (R = 20000) of IN Com in the region of the H_α, H_β, and He I 5876 lines. One distinguishing characteristic of the stellar spectrum is the presence in the H_α line of an extended two-component emission with limits up to ±400 km/s. Emission parameters show the rotation modulation with the stellar rotation period and a significant variability on the long-term scale. Similar emissions are also observed in the H_β and He I 5876 lines. Our results allow us to conclude that observational emission profiles are formed in an optically thin hot gas. This is a result of the presence of a circumstellar gas disk around IN Com. Its size does not exceed several stellar radii. The material for the disk is supported by the stellar wind from IN Com. The detected variability of H_α-emission parameters shows a clear connection with the photopolarimetric activity of the star. This fact allows us to associate the long-term spectral variability with cycles of stellar activity of IN Com.