Analysis of the nonstationarity of the atmosphere of α Cyg. III. Variability of the Hα-line profile

The temporal variations of the radial velocity and profile of the Hα line in the spectrum of α Cyg are analyzed based on 240 CCD spectra taken with the coude spectrograph attached to the 2-m telescope of Shamaha Astrophysical Observatory of the National Academy of Sciences of Azerbaijan in 1998–2000. The results obtained are inconsistent with the conclusion made by the Heidelberg group concerning the behavior of the variability of the Hα-line profile [1]. The observed pattern of radial-velocity variations is due to nonradial pulsations and differs for the blue and red halves of the absorption profile. The pulsation parameters differ for different levels of residual intensity for both halves of the absorption profile. The amplitude and period increase from the core toward the wing of the line for the red half of the absorption profile, and, on the contrary, decrease toward the line wing for the blue half of the profile. Absorption features are observed on the blue half of the absorption profile. Their emergence and disappearance, as well as minor migrations are indicative of the clumpy structure of the stellar envelope. The similarity of the variability behavior of the absorption and emission profiles indicates that the latter too owe their variability to nonradial pulsations. Thus the variability of the stellar wind in its formation regions is partly due to the nonradial pulsations of the underlying layers of the atmosphere. On the whole, the variability of the position and photometric parameters of the absorption and emission components of the profile is indicative of the nonstationary nature and asymmetric shape of the stellar wind.     

Investigation of Galaxies of the Second Byurakan Sky Survey. V. Spectroscopic Observations in the Field of 12h22m, +55°

The results of spectroscopic observations of 28 galaxies of the Second Byurakan Sky Survey, completing the follow-up spectroscopy of galaxies in the survey field with central coordinates = 12^h22^m, = +35°, are presented. The spectra were obtained on the 2.6 m telescope of the Byurakan Astrophysical Observatory, National Academy of Sciences of the Republic of Armenia, and the 6 m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences. The redshifts and absolute stellar magnitudes of all the galaxies have been determined. A preliminary analysis of the spatial distribution of all galaxies in this sample is given.     

Investigation of galaxies of the second byurakan sky survey. II. Spectroscopic observations in the 08h00m, +59° field

The results of spectroscopic observations of 25 objects of the Second Byurakan Spectroscopic Sky Survey in a field with central coordinates a = 08^h00^m, δ = +59° are given. The spectra were obtained on the 2.6- m telescope of the Byurakan Astrophysical Observatory, National Academy of Sciences of the Republic of Armenia, and the 6- m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences, in 1997– 1998 with a spectral resolution of from 5 to 15Å. The redshifts and absolute stellar magnitudes of all the galaxies were determined and they were classified. A histogram of the redshift distribution of the complete sample of galaxies in this field of the survey is given.     

Investigation of Galaxies of the Second Byurakan Sky Survey. III. Spectroscopic Observations in the Fields of 09h47m, +51° and 09h50m, +55°

The results of observations of 49 objects from the second Byurakan spectroscopic sky survey are given; they complete the recent spectroscopy of galactic samples in the fields centered on the coordinates = 09^h47^m, = +51° and = 09^h50^m, = +55°. The spectra were obtained on the 2.6-m telescope of the Byurakan Astrophysical Observatory, National Academy of Sciences of the Republic of Armenia, and the 6-m telescope of the Special Astrophysical Observatory, Russian Academy of Sciences, during 1998-2000. Redshifts and absolute stellar magnitudes were determined for all the galaxies.     

Investigation of Galaxies of the Second Byurakan Sky Survey. IV. Spectroscopic Observations in the Fields of 11h30m, +59° and 12h00m, +59°

Spectroscopic observations of 71 objects have completed the follow-up spectroscopy of galaxies in two adjacent fields of the Second Byurakan Survey with central coordinates = 11^h30^m, = +59° and = 12^h00^m, = +59°. The spectra were obtained on the 2.6-m telescope of the Byurakan Astrophysical Observatory and the 6-m telescope of the Special Astrophysical Observatory. The redshifts and absolute stellar magnitudes of all the galaxies have been determined. The objects have been classified using an adapted scheme.     

Rhombic Cell Analysis - A New Way of Probing the Large- Scale Structure of the Universe. I.General Considerations

A new way of probing the harge-scale structure of the universe is proposed.Space is partitioned into cells the shape of rhombic dodecahedron.The cells are labelled “filled“ or “empty“ according as they contain galaxies or not ,the cell size is so chosen as to have narly equal numbers of filled and empty cells for the given galaxy sample.Two observables on each cell are definable:the number of ist like neighbors,n1,and a two-suffixed topological type τ,the suffixes being the numbers of its like and unlike neighbor-groups.The frequency distributions of n1 and τ in the observed set of filled(empty)cells are then considered as indicators of the morphology of the set,The method is applied to the CfA catalogue of galaxies as an illustration.Despite its limited size,the data offers evidence 1) that the empty cells are more stongly clustered than the filled cells,and 2) theat the filled cells,but not the empty cells,have a tendency to occur in sheets,Further directions of development both in theory and application are indicated.     

Identification of peculiar A-stars. I. Analysis of the equivalent width of the 2786–2810 Å spectral band and the MgII 4481 Å line for 137 A-stars

The dependence of the equivalent widths of the 2786–2810 Å spectral band and the MgII 4481 Å line on the basic parameters (T_eff, logg and [M/H]) for 137 bright A-stars shows that 60 of them are candidate peculiar stars. Given the similar behavior of W(2800) and W(4481), it can be assumed that 34 of the stars are chemically peculiar stars. The anomalous values of W(2800), W(4481), and [M/H] vary over wide limits for the rest of the stars, possibly because they are binary. Translated from Astrofizika, Vol. 51, No. 4, pp. 577–593 (November 2008).     

Far infrared photometry of planets: Saturn and Venus: Volume 38, Number 3 (1979), in the article,by R. Courtin,P. Léna,M. De Muizon,D. Rouan,C. Nicollier,and J. Wijnbergen,pp. 411–419

The global distribution of existing lunar topography suffers from a lack of measurements of far-side radii because of the sparsity of data types in the nonequatorial regions. This paper presents determinations of far-side lunar radii based on the reduction of photogrammetric measurements derived from selected Apollo 16 trans-Earth phase photographs. The regions covered in this analysis lie west of Mare Moscoviense between longitudes 90 and 130°E and latitudes 10 and 60°N. The determinations are made using control points appearing on both NASA topographic orthophoto maps and the Apollo 16 photographs. The estimated lunar radii are referred to these control points and determined with a relative accuracy of 500 m. The new lunar radii are used to generate a topographic map covering the area investigated. The map shows that, with the given spatial density of surface festures measured, basin-sized features can be resolved. In particular, the far-side craters Fabry, Riemann, and Szilard comprise a topographically depressed region about 500 km in diameter centered at 120°E and 38.5°N. The floor of this basin is 2.4 to 3.4 km below the reference sphere of 1738.0 km and 4.8 to 5.8 km below the northern rim of the basin. A comparison of the depth of the unfilled basin with the depths of maria-filled front-side basins leads to the conclusion that basalt fill of the near-side maria may be 2 km deep. The topographic map shows good correlation with geologic provinces of young plains and cratered terra in the far-side highland region investigated. Lack of correlation between sampled values of the state-of-the-art 16th-order and 16th-degree harmonic gravity field model and corresponding topographical values leads to the conclusion that the far-side region investigated is isostatically compensated.     

Speckle interferometry of magnetic stars with the BTA. II. Results of 2010–2012 observations

We present the results of speckle interferometric observations of 156 stars possessing global magnetic fields, carried out with the 6-m BTA telescope of the Special Astrophysical Observatory. Virtually all stars were observed between 2010 and 2012. Thirty-four stars were resolved into individual components (31 double and 3 triple), of which 14 binary systems (BD+41○43, HD2887, HD30466, HD36540, HD36955, HD37479, HD61045, HD89069, HD144334, HD164258, HD349321, HD343872, HD184471, HD196691) and 2 triple systems (HD37140, HD338226) were for the first time resolved by the astrometric method.     

Physical parameters of multiple systems like the trapezium of early spectral types, derived fromuvbyβ photometry. II

The effective temperatures T_eff, gravitational force g at the stellar surface, and Fe/H have been calculated for 50 components of 15 Trapezia of early spectral types from electrophotometric observations in the six-color uvbyβ photometric system. The results of the calculation showed that the log T_eff of Trapezia components lie in the range 4.03–4.54, while their log g lie in the range 2.58–4.02. The atmospheric parameters T_eff and g were used to determine the stars’ masses and ages based on Hejlesen’s calculated evolutionary model sequences. All the Trapezia components have several times more mass than the sun and almost half of them have over 10 times that mass. Over 70% of the components are less than 40.10⁶ years old. Translated from Astrofizika, Vol. 41. No. 2. pp. 235–244, April-June, 1998.     

A Study on the Recovery and Classification of Meteorites from the Mt. Grove Region of Antarctica

The Antarctic Continent has become the largest natural preservatory of meteorites in the world because of its unique geographical position and climatic conditions. Mt. Grove is located in the inland area of the Antarctic Continent where the conditions are favorable for the preservation of meteorites. During China's 15th, 16th and 19th Antarctic Scientific Explorations a large number of meteorites were recovered in the Mt. Grove region. Especially during the 19th Exploration in 2002/03 a total of 4448 meteorites were recovered, which at one stroke put China among countries that have recovered most numbers of meteorites. Here, we report mainly the results of microscope and electron microprobe studies of 28 meteorites recovered during the 16th Exploration. The meteorites are chemically classified based on their mean Fa contents of olivine, mean Fs contents of low-Ca pyroxene and abundances of Fe-Ni metal. We also give a brief account of the meteorite recovery during the three Explorations and of some preli     

Molecular dynamics estimates for the thermodynamic properties of the Fe–S liquid cores of the Moon,Io, Europa,and Ganymede

A molecular dynamics (MD) simulation is performed for the physical and chemical properties of solid and liquid Fe–S solutions using the embedded atom model (EAM) potential as applied to the internal structure of the Moon, Io, Europa, and Ganymede under the assumption that the satellites' cores can be described by a two-component iron–sulfur system. Calculated results are presented for the thermodynamic parameters including the caloric, thermal, and elastic properties (specific heat, thermal expansion, Grüneisen parameter, density, compression module, velocity of sound, and adiabatic gradient) of the Fe–S solutions at sulfur concentrations of 0–18 at %, temperatures of up to 2500 K, and pressures of up to 14 GPa. The velocity of sound, which increases as pressure rises, is weakly dependent on sulfur concentration and temperature. For the Moon’s outer Fe–S core (~5 GPa/2000 K), which contains 6–16 at % (3.5–10 wt %) sulfur, the density and the velocity of sound are estimated at 6.3–7.0 g/cm³ and 4000 ± 50 m/s, respectively. The MD calculations are compared with the interpretation of the Apollo observations (Weber et al., 2011) to show a good consistency of the velocity of P-waves in the Moon’s liquid core whereas the thermodynamic density of the Fe–S core is not consistent with the seismic models with ρ = 5.1–5.2 g/cm³ (Garcia et al., 2011; Weber et al., 2011). The revision the density values for the core leads to the revision of its size and mass. At sulfur concentrations of 3.5–10 wt %, the density of the Fe–S melt is 20–30% higher that the seismic density of the core. Therefore, the most likely radius of the Moon’s outer core must be less than 330 km (Weber et al., 2011) because, provided that the constraint on the Moon’s mass and moment of inertia is satisfied, an increase in the density of the core must lead to a reduction of its radius. For Jupiter’s Galilean moons Io, Europa, and Ganymede, constraints are obtained on the size, density, and sound velocity of the Fe–S liquid cores. The geophysical and geochemical characteristics of the internal structure of the Moon and Jupiter’s moons are compared. The calculations of the adiabatic gradient at the P–T conditions for the Fe–S cores of the Moon, Io, Europa, and Ganymede suggest the top-down crystallization of the core (Fe-snow scenario).