On the metallogenic role of craton terrains in the marginal sea lithosphere

The metallogenic efficiency of the marginal sea lithosphere of Northeastern Asia is associated mainly with the ore formation variety of the remaining cratons and microcratons that defined the structural peculiarity of the region; these are setoffs of the Precambrian basement, brachyform, anticline highs, and genesis of rifts within TMA periods. These formations allowed us to explain the reasons for the unique metal-bearing feature of the marginal sea lithosphere of the Pacific Ocean ore belt in addition to phenomena of an inherited nature of mineralization and conditions of formation of polychronous ore deposits.     

Diversity of hydrothermal processes and different types of epithermal deposits

It is shown that classical epithermal deposits with hydrothermal explosions, brecciated and framework–lamellar (including agate-like) structures, and well-developed bonanzas are usually pre-porphyry in origin. This inference seems to be important for development of the genetic model of a porphyry–epithermal ore-forming system as well as for exploration of gold–silver deposits and assessment of their potential.     

Variability of the Blazar 4C 38.41 in 2006–2017

The results of multicolor photometric and polarization observations of the blazar 4C 38.41 (Q 1633+382) performed at St. Petersburg State University, the Pulkovo Astronomical Observatory of the Russian Academy of Sciences, Boston University, and Steward Observatory in 2006–2017 are analyzed. Separate variable sources responsible for the observed activity are distinguished, whose power-lawspectra and high degree of polarization confirm their synchrotron nature. The observed color variability of the object (redder when brighter) can be explained by an increase in the contribution to the total emission of a red component with variable flux and a constant relative spectral energy distribution. A close correlation between the optical and gamma-ray light curves is identified, suggesting the same location of the variable sources responsible for the radiation in these bands.

     

Field studies of variation scales of gravitational capillary waves and near-water wind in the Black Sea shelf area

In this study we present the results of data processing from the 2004 Gelendzhik Bay expedition on the Akvanavt research vessel. The data were processed using the method of wavelet analysis. We found an emerging kilometer-scale variation in the surface heaving and near-water wave over the shelf area. This effect was shown to be possibly caused by the inhomogeneity of current in the depth-drop area.     

V475 Sct (Nova Scuti 2003) – Binary or Triple System?

UBV RI photometry and 4600–9000 Å spectroscopy of nova V475 Sct taken in the first 3 month after discovery is presented. The object can be classified as a Fe II type slow nova with t _2,V = 48 days, t _3,V = 53 days. The absolute magnitude of the nova at maximum, its colour excess and distance were determined. The observed 13.4 day periodicity of flares can be explained by the mass transfer bursts from the red to the white dwarf, probably caused by the periastron passage of a third body. Two sets of absorptions are seen in the P Cyg-type Hα line profile. They arise in the expanding shell of the nova.     

The Unique Binary Star α Coronae Borealis

We present a new photoelectric light curve of α Coronae Borealis. The derived rate of apsidal motion differs from the theoretical prediction. A possible solution of the problem is suggested.     

Analysis of thermospheric density variations neglected in modern atmospheric models using accelerometer data

The accuracy of the atmospheric density and its spatiotemporal variations given by the NRLMSISE-00 atmosphere model at the solar minimum are estimated using density measurements of the CACTUS microaccelerometer at heights of 270–600 km. The model errors are found to be noticeably (by a factor of 2–3) higher than the errors in atmospheric densities obtained from satellite drag data at solar minima. Microaccelerometer density data are used to study short-period (during one orbit) spatiotemporal density variations. The analysis of density variations over one orbit reveals orographic and continental effects. The amplitudes of the continental and orographic effects are estimated at 10–15% at a height of 270 km and 40% at a height of 600 km.