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21.
The rotational velocities of young stars of the UX Ori type and related objects are analyzed. It is shown that there is a
weak but statistically significant correlation between υsin i and the amplitudes of photometric variability of these stars.
It reflects the fact that the brightness variability of this type of star is determined mainly by variations in the column
density of circumstellar dust along the line of sight. The latter depends, in turn, on the orientation of the circumstellar
disk and is greatest when the disk is oriented edgeon to the observer or at a small angle to the line of sight.
Translated from Astrofizika, Vol. 43, No. 3, pp. 329-337, July– September, 2000. 相似文献
22.
O. E. Kozlov S. N. Aleksashkin A. V. Ivanov T. O. Kozlova S. E. Sutugin 《Solar System Research》2010,44(5):451-455
This paper is devoted to the problem of sampling with the use of a manipulator during the mission of the Phobos-Grunt spacecraft. The principle of operation accepted for the chosen engineering solution, as well as the construction of the manipulator
scoop, mechanical gears, and the manipulator as a whole, are considered; brief technical specifications are given. The issue
of the selection of the soil as an analog of the soil of Phobos to conduct ground-based tests is discussed; the test results
and principles of the manipulator operation and control are presented. 相似文献
23.
A new method is proposed for studying the population of distant radio sources. It is based on building the average continuum radio spectrum for objects located within the given redshift interval. In this paper the redshift bin size dz is set equal to 0.1. The data about the average spectra can theoretically be used to study the distribution of the large-scale structure and the features of its formation. On the practical side the average spectra at different z can be used to simulate the distribution of radio sources, which is required in various computational tasks. The change of the form of the spectrum at different z is indicative of the cosmological evolution of the population of radio sources. 相似文献
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25.
Heiko Sahling Gerhard Bohrmann Yuriy G. Artemov André Bahr Markus Brüning Stephan A. Klapp Ingo Klaucke Elena Kozlova Aneta Nikolovska Thomas Pape Anja Reitz Klaus Wallmann 《Marine and Petroleum Geology》2009
Vodyanitskii mud volcano is located at a depth of about 2070 m in the Sorokin Trough, Black sea. It is a 500-m wide and 20-m high cone surrounded by a depression, which is typical of many mud volcanoes in the Black Sea. 75 kHz sidescan sonar show different generations of mud flows that include mud breccia, authigenic carbonates, and gas hydrates that were sampled by gravity coring. The fluids that flow through or erupt with the mud are enriched in chloride (up to ∼650 mmol L−1 at ∼150-cm sediment depth) suggesting a deep source, which is similar to the fluids of the close-by Dvurechenskii mud volcano. Direct observation with the remotely operated vehicle Quest revealed gas bubbles emanating at two distinct sites at the crest of the mud volcano, which confirms earlier observations of bubble-induced hydroacoustic anomalies in echosounder records. The sediments at the main bubble emission site show a thermal anomaly with temperatures at ∼60 cm sediment depth that were 0.9 °C warmer than the bottom water. Chemical and isotopic analyses of the emanated gas revealed that it consisted primarily of methane (99.8%) and was of microbial origin (δD-CH4 = −170.8‰ (SMOW), δ13C-CH4 = −61.0‰ (V-PDB), δ13C-C2H6 = −44.0‰ (V-PDB)). The gas flux was estimated using the video observations of the ROV. Assuming that the flux is constant with time, about 0.9 ± 0.5 × 106 mol of methane is released every year. This value is of the same order-of-magnitude as reported fluxes of dissolved methane released with pore water at other mud volcanoes. This suggests that bubble emanation is a significant pathway transporting methane from the sediments into the water column. 相似文献
26.
Quasi-simultaneous photoelectric and spectroscopic observations have been made of the active spotted star VY Ari, showing an increase in the equivalent width of pure emission in the H line with a decrease in the star's brightness. Such an increase indicates a relationship between active regions in the chromosphere and the cool photospheric spots. The photometric variability of VY Ari can be described entirely in terms of a zonal model. The spotted regions occupy up to 41% of the star's total surface, with the temperature difference between the quiet photosphere and a spot of 1300 K. The spots lie at middle and low latitudes. 相似文献
27.
Quasisimultaneous photoelectric, polarimetric, and spectroscopic observations of the active single red dwarf LQ Hya are presented. The photometric variability of LQ Hya is fully described by a zone model. Spotted regions occupy up to 25% of the entire surface of the star with a temperature difference of 800 K between the spots and the calm photosphere. The spots are localized in the middle and low latitudes. A cyclical variation is observed in the total areas of the spotted regions and in the average latitude of the spots. The most spotted regions, local magnetic fields, and chromospherically active regions tend to concentrate in the same distinct active longitudes. 相似文献
28.
Results of simultaneous spectral and photometric monitoring of the Ae Herbig star WW Vul in the neighborhoods of the Ha line
and the sodium NaI D resonance doublet are reported. It is shown that the spectral variability of the star is caused mainly
by the anisotropic disk wind, whose high velocity component forms in the inner region of the accretion disk. The circumstellar
gas in footpoint of the wind shows the variability of the density and velocity, that is in good agreement with the results
of modeling of an accretion and outflows around young stars controlled by the stellar and/or disk magnetic field. An analysis
of the variability of the parameters of the Ha emission line also showed that the density of the gas in the inner region of
the accretion disk varies over a time scale exceeding 10 years.
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Translated from Astrofizika, Vol. 49, No. 2, pp. 171–185 (May 2006). 相似文献
29.
Danilov-Danilyan V. I. Kozlova M. A. Polyanin V. O. Chesnokova I. V. 《Water Resources》2022,49(4):525-532
Water Resources - The present-day knowledge of Crimean water resources is analyzed; the data on surface water and, the more so, deposits of groundwater, as well as the interaction between them are... 相似文献
30.
E. N. Poludetkina M. B. Smirnov N. P. Fadeeva E. V. Kozlova 《Geochemistry International》2017,55(8):726-736
Samples of carbonate and siliceous-carbonate deposits of Semiluk—Sargaev horizons of the N?NE slope of the South Tatar uplift, Volga-Ural petroliferous basin, have been studied. Specific feature of the source rocks—high concentration of compounds—anoxia testifiers in the photic layer has been identified. That is, organic matter has been deposited under the conditions of the constant presence of anoxia in the photic layer of the sedimentation basin at sufficiently high thickness of the water column contaminated with hydrogen sulfide. Since by the composition of saturated hydrocarbons the studied samples are typical for deposits of the Semiluk horizon of the central part of the Volga-Ural basin, we can assume a fairly wide prevalence of such conditions within the South-Tatar arch. Changes in the concentrations of the components—anoxia markers—show cyclical changes in output layer contaminated with hydrogen sulfide or its bioproduction within the studied time. 相似文献