Physical parameters and orbit of the eclipsing binary BD +66 1663 = GSC 4479 412

We have obtained the first UBV(RI) _C photoelectric light curves of the recently discovered eclipsing binary BD +66 1663 = GSC 4479 412 (P = 7.04^d, V = 10.14). We have derived relative and absolute parameters of the binary, and analyzed the interstellar extinction towards the object. Though the star is located in the field of the young open cluster Be 59, we demonstrate that it is not a member.     

Apsidal motion and physical parameters of the eclipsing binary system AR Cas

Using the four-channel automatic photoelectric photometer of the Sternberg Astronomical Institute’s Tien Shan Mountain Observatory, we have acquired accurate (σ_obs≈0.004^m) W BV R brightness measurements for the eclipsing binary AR Cas during selected phases before eclipse ingress and after egress, as well as at the center of minima. A joint analysis of these measurements with other published data has enabled us to derive for the first time a self-consistent set of physical and geometrical parameters for the star and the evolutionary age of its components, t=(60±3)×10⁶ years. We have found the period of the apsidal motion (U_obs=1100±160 years, \(\dot \omega _{obs} = 0^\circ .327 \pm 0^\circ .049\) years^?1) and the apsidal parameter of the primary, logk _2,1 ^obs =?2.41±0.08, with the apsidal parameter being in good agreement with current models of stellar evolution. There is an ultraviolet excess in the primary’s radiation, Δ(U?B)=?0.12^m and Δ(B?V)=?0.06^m, possibly due to a metal deficiency in the star’s atmosphere.     

Physical parameters of the eclipsing binary V798 Cep

The first high-accuracy CCD UBV RI(RI)_C light curves for the recently discovered eclipsing binary V798 Cep (P = 16 ^d .08, V = 11 ^m . 8) are presented; this star is included in our program of eclipsing systems with considerable eccentricities. A photometric solution for the light curves and physical characteristics of the component stars are derived. The orbital eccentricity is quite high, e = 0.437. The longitude of periastron is close to 180°, making studies of the apsidal motion difficult. V798 Cep may be a hierarchical system.     

Multiplicity and apsidal motion in the eclipsing binary EQ Boo

We present the first estimates of the relative and absolute parameters of the eclipsing binary EQ Boo based on a light-curve analysis (P = 5.43^d, V = 8.8 ^m ). This star is simultaneously Component A of the visual binary ADS 9422 (spectral types F7V + G0V; separation of the components 1.3″; magnitude difference 0.7 ^m ). The derived disagreement between the components’ physical parameters and the assumption that they have the same age can be removed if there is a fourth, late-type star in the system. This is also able to explain the observed anomaly in the behavior of the O-C residuals at times of minima.     

Photometric elements and apsidal motion of the eclipsing binary ES Lac

We have obtained high-accuracy photoelectric measurements of ES Lac, an eclipsing binary with an elliptical orbit (B9III + B9III; P = 4.459^d, e = 0.198) in 1985–2004 at the Sternberg Astronomical Institute’s Tien Shan High-Altitude Observatory. Our detailed analysis of the 19-year uniform series of measurements has yielded the first photometric elements for this system, as well as a self-consistent set of physical and geometrical parameters for the binary. The virtually identical components (M ₁ = M ₂ = 3.0 M _⊙; R ₁ = R ₂ = 4.12 R _⊙) are appreciably separated from the main sequence, and are located on the giant branch: their age is t = (3.5 ± 0.2) × 10⁸ yrs. An analysis of our observations together with previously published times of minima has enabled a considerable refinement of the period of the apsidal motion, U = 355 ± 20 years, and a first determination of the apsidal parameter reflecting the radial density distributions for the components stars: k ₂ ^obs = 0.00213(18). This value is in a good agreement with the value expected theoretically for current evolutionary models of such stars: k ₂ ^th = 0.00257(15).     

The eclipsing binary HS hercules: Photometric elements and the evolutionary stages of its components

We used a photoelectric photometer designed by V.M. Lyutyi and the Zeiss-600 telescope of the Sternberg Astronomical Institute’s Crimean Observatory to acquire precise UBV brightness measurements (σ _obs ^V ～ 0.007^m) for the eclipsing binary system HS Her in 1984–1991. These measurements continue the homogeneous series of observations of this star commenced in 1969 by D.Ya. Martynov using the same equipment. Our detailed analysis of this homogeneous 22-year series of photoelectric observations has yielded a self-consistent set of physical and geometric parameters of the binary, and enabled us to establish the evolutionary stages of its components. The systems’s primary, M ₁ = 5 M _⊙, is at the beginning of its main-sequence evolution, whereas its secondary, M ₂ = 1.6 M _⊙, has not yet reached the main sequence. The binary’s age is estimated to be t = (17 ± 3) × 10⁶ years.     

The third body in the eclipsing system RR Lyn

Based on 70 years of published photoelectric observations, we have detected quasi-periodic cophased oscillations of the times of the primary and secondary minima of RR Lyn, one of the brightest and nearest eclipsing binaries in the northern sky ( $V = 5\mathop m\limits_. 54$ ; r=74 pc). Approximating these oscillations using the light equation yields estimates of the orbital parameters of the third body in the system and imposes constraints on its mass, M ₃. In the most probable case when the orbits of the eclipsing and triple systems are coplanar, M ₃=1.10±0.02M _⊙, and the semimajor axis of the orbit A ₃=17.4±3.5 AU, with a substantial eccentricity, e ₃=0.96±0.02. We have carried out a detailed study of the apsidal rotation of this eclipsing and now multiple system, which was suggested by Koch as a test of general relativity as far back as 1973. Our high-precision W BV R photoelectric photometry $(\sigma _{obs} \cong 0\mathop m\limits_. 0032)$ has removed some contradictions. At the same time, the proximity of the longitude of periastron ω 180°; the close correlation between the jointly estimated values of ω, e and the limb-darkening coefficients for the component disks, u ₁ and u ₂; and microfluctuations in the brightnesses of the stars prevent determination of the rate of rotation of the elliptical orbit in the system, even using the most accurate measurements.     

The eclipsing WN3(h)+O5V binary BAT99-129: Light curve analysis and parameters of its components

We have analyzed the broad-band light curve of the massive eclipsing binary BAT99-129, which is located in the Large Magellanic Cloud and consists of WN3(h) and O5V components. The light curve was obtained as part of the MACHO project. The dense extended atmosphere of the Wolf-Rayet (WR) star makes it impossible to apply a standard parametric model, such as that of Wilson and Devinney, to analyze the light curve. We reconstructed the distributions of the brightness and absorption across the disk of the WR component by directly solving the integral equations describing the eclipses in the system. Our analysis yields reliable estimates of the system’s orbital parameters and the parameters of its components. The orbital inclination is 78°, the size of the orbit 28.5 R _⊙, and the radius of the O component R _O = 7.1 R _⊙. The size of the WR core, which is opaque in the optical continuum, is R _WR = 3.4 R _⊙, and the brightness temperature at the center of the WR-component disk is T _br = 45 000 K. We discuss possible uncertainties in the parameters obtained. The derived information is used to draw conclusions about the system’s evolutionary status.     

Photometric elements,apsidal motion,and the third body in the eclipsing binary V974 Cyg

We have derived the first photoelectric light curve of the eclipsing binary V974 Cyg from our own photoelectric observations. Analysis of the light curve has yielded the system’s photometric elements (r ₁ ≈ r ₂ = 0.1192, e = 0.058, L ₁ ≈ L ₂ = 0.486, and L ₃ = 0.028) and absolute parameters (M ₁ ≈ M ₂ = 2.2M _⊙, T _eff,1 ≈ T _eff,2 = 9500 K, a = 15.0R _⊙, distance d = 1.29 kpc, age log t = 8.0, t/tMS = 0.11). We have detected apsidal motion with the period U _obs = (1140 ± 170) yrs, and the presence of a third body in the system. The orbital parameters derived for the third body are P ₃ = 26.5 yrs, e ₃ = 0.78, and a ₃ sin i ₃ = 1.5 AU; and the lower limit for its mass is M ₃ > 0.58M _⊙. The observed apsidal-motion rate is higher than is expected theoretically by a factor of 1.5. The axial rotation of the system’s components is not yet synchronized with the orbital motion, probably because V974 Cyg is relatively young and detached.     

Interpretation of the light curve of the eclipsing binary V444 Cyg on the set of convexo-concave functions

The narrow-band λ4244 Å continuum light curve of the eclipsing binary V444 Cyg, which has a Wolf-Rayet component, is interpreted assuming that the brightness distribution and absorption in the WN5 star's disk are monotonic, non-increasing, convexo-concave, non-negative functions. The convex and concave parts of these functions correspond to the core of the WN5 star and its extended photosphere and atmosphere, respectively. The radius and brightness temperature of the opaque core of the WN5 star are r _WN5 ^core ? 4R _⊙ and T _br ^core >52000 K, respectively. The stellar wind is characterized by an accelerated radial outflow. Acceleration of the wind persists at large distances from the center of the star. A crude Lamers-law fit to the reconstructed velocity field in the wind yields an acceleration parameter β=1.58–1.82.     

Precision W BV R photoelectric photometry of the eclipsing system RR Lyncis

We carried out accurate ( $\sigma _{obs} \approx 0\mathop .\limits^m 003$ ) W BV R photoelectric photometry of RR Lyn and obtained light curves of this eclipsing system. Our analysis of the light curves using an iterative differential-correction method yields a self-consistent system of geometrical and physical characteristics of the two components of the system and their evolutionary states. The system's age is estimated to be t=(1.08±0.15)×10⁹ yr. Observations in all filters are fitted satisfactorily by the same geometry (r _1,2, i, e, and ω). An analysisof blanketing effects in the W, B, V, and R bands indicates that the atmospheric chemical compositions of both components of the system are peculiar: the primary shows an excess ([Fe/H]_I=0.31±0.08) and the secondary a deficit ([Fe/H]_II=?0.24±0.06) of heavy elements. This is in qualitative and quantitative agreement with the results of an earlier spectroscopic study of RR Lyn by Lyubimkov and Rachkovskaya (1995). The derived physical characteristics of RR Lyn provide evidence that the metallicity effects are probably restricted to the stellar surface layers, while their interiors have normal chemical abundances.     

The structure of the common envelope in a close binary system

As a result of the interaction between an elliptical accretion disk and gas flowing into it from the circumbinary envelope in a close binary in the course of its orbital motion, the matter of the disk and the circum-disk halo is periodically ejected from the vicinity of the Lagrange point L₃, and a common envelope is formed in the system. Three-dimensional numerical gas-dynamical modeling is used to study the structure and dynamics of the envelope and determine its basic parameters. The evolution of the envelope is followed on timescales of the order of several orbital periods. The matter flow ejected through the vicinity of L₃ displays a spiral shape. The maximum size of the forming spiral structure is restricted by the self-intersection point, and is of the order of four to five times the component separation. We consider the dynamics of the regions directly adjacent to the spiral structure: an inner, rarified and outer, fragmented region, which further makes a transition to an expanding diffuse ring.     

The physical parameters of several extragalactic radio sources displaying rapid variability

We present the results of a study of the sources PKS 0405-385, B0917+624, PKS 1257-326, and J1819+3845, which display variability on time scales from 1–7 h (at 5 GHz). Estimates of the physical parameters (magnetic-field intensity, density of relativistic particles, energies of the magnetic field and relativistic particles) are given for B0917+624 and J1819+3845. It is shown that these sources are not in a state of energy equipartition. A number of indirect arguments indicate that the shortest flares in sources with long-time-scale variability have the same parameters as flares in the studied sources.     

Spots on the surfaces of the chromospherically active stars GSC 08923-01147 and GSC 08933-01802: Observational data of the ASAS-3 project

Active regions on the surfaces of the chromospherically active stars GSC 08923-01147 and GSC 08933-01802 are found by reconstructing the surface-temperature inhomogeneities using the V light curves, obtained from observations performed during the ASAS-3 project. Up to one-third of the total observed area of the stellar surfaces was covered by spots. In GSC 08923-01147, the spotted fraction decreased from 0.31 to 0.05 during the observation period, while it varied within 0.2–0.3 during four years in GSC 08933-01802. The detected phases of active longitudes tend to concentrate near two positions separated by about half a period. The active regions in GSC 08933-01147 became closer or further apart on a time scale of 4.8 years. The maximum separations of the longitudes Δφ _long were maximum when the amplitude of the brightness variability reached a minimum. During the transition of the star from a minimum-brightness to an enhanced-brightness state, the longitude of the more active region switched. The brightness variability of GSC 08933-01802 was more substantial (ΔV }~ 0.55 ^m −0.06 ^m ). For some time, only one extended active region was present on the stellar surface, while two regions were usually present. No switch of the active longitudes was detected. The more active region monotonically moved over the surface of the star, causing the longitudes of the active regions to drift together. This monotonic change in the position of the more active longitude ceased at the minimum of the brightness-variation amplitude.     

The rank evaluation of South Brazilian Gondwana coals on the basis of different chemical and physical parameters

Rank evaluation of South Brazilian Gondwana coals according to the American (American Society for Testing and Materials, ASTM) and German (Deutsche Industrie Normen, DIN) standard specifications or on the basis of Alpern's Universal Classification has too often led to conflicting results.When any attempt is made to determine the rank of Brazilian coals by using methods established for the Northern Hemisphere coals, two sorts of difficulties arise: namely, (1) the reflectence measurements do not indicate the real degree of coalification of the organic matter because of the liptinitic impregnations of the vitrinites, and (2) random reflectance values (R_ran, moisture, volatile-matter and carbon contents as well as the calorific value do not correlate when plotted on the ASTM and DIN classification schemes.In addition, when rank determinations are carried out by using fluorescence measurements and geochemical analyses the results are at variance in relation to those determined by the conventional chemical and physical parameters.It is suggested that the rank evaluation of South Brazilian coals is far more meaningful if carried out by reflectance measurements on vitrinites along with fluorescence measurements on sporinites, alginites and coal extracts.     

Corresponding states in binary solutions,and graphical determination of Margules parameters

The thermodynamic properties of non-ideal binary solutions were investigated. By using reduced temperatures (T/T _{critical mixing}) and comparing the width of the solvi in very different binary systems, a uniform relation for several systems is obtained for which the concept of corresponding solvi is introduced.A graphical method is developed to determine Margules parameters from two-phase regions in solid solutions. Graphs are presented for binodal — as well as spinodal solvi. The Margules parameters obtained with these graphs are comparable with the calculated ones.In well investigated systems from the literature constant ratios of Margules parameters (W _a /W _b ) were recognized so far. Combining this observation with the concept of corresponding solvi, a tentative solvus can be constructed with a minimum of data.List of Symbols Used in the Calculations x Mole fraction of component B in solid solution - x ₁ Mole fraction of component B in phase 1 - x ₂ Mole fraction of component B in phase 2 - _A ⁰ Chemical potential of 1 mole pure component A - _B ⁰ Chemical potential of 1 mole pure component B - _A(x), _A Chemical potential of component A in solid solution - _B(x), _B Chemical potential of component B in solid solution - G Total Gibbs energy of the system - ¯G _m (x), ¯G_m Molar Gibbs energy of solid solution - ¯G _m ^E (x) Excess function - W _a , W _b Margules parameters - T Absolute temperature in K - P Pressure     

Relative variations of the physical parameters of variable extragalactic radio sources

A method for studying the physical conditions in compact components of extragalactic radio sources displaying variability on time scales of hundreds of days is proposed. The method can be used to estimate the relative variations of the magnetic-field strength and number density of relativistic electrons in superluminal jets from the cores of quasars and radio galaxies. Results are presented for the jets of the quasars 3C 120, 3C 273, 3C 279, and 3C 345. The energies of the magnetic field and relativistic particles in these objects are not in equipartition. As a rule, the magnetic-field strength decreases appreciably during the evolution of an expanding jet, while the number of relativistic electrons grows.     

The Physical Meanings of 5 Basic parameters for an X-Ray Diffraction Peak and Their Application

This paper derives the physical meanings of peak position,peak width and hight of an X-ray diffraction peak from the analyses of the Bragg‘s equation,the Scherrer‘s formula and the principle of peak intensity calculation.The geometric characteristics of an asymmetric peak are clarified by means of experimemt.The relationships between peak shape and domain size/lattice strain have been verified by geological events.Therefore thsi paper integrates the physical meanings of all 5 basic parameters for an -Xray diffraction peak.Applications of these 5 parameters are exemplified.     

The effect of combined countermeasures on main local scouring parameters using physical models

Details of an experimental study for 22 clear-water scour tests around bridge piers are presented in three combinations of flow-altering countermeasures against bed erosion. The combined countermeasures are as follows: (1) berm and geometry; (2) berm, geometry, and centered slot; and (3) berm, geometry, and off-centered slots. First, four different cross-sections were selected for the model piers (A series). The results of this group have shown that the lenticular model can decrease the scour depth remarkably. The efficient height of a berm was then determined through B series of tests for circular cylindrical model pier. Then, it was found that the first combination (C series) could not decrease the bed erosion significantly. Also, the second combination (D series) mainly decreased the scour depth only in the circular and round-nosed rectangular geometries. Finally, the third combination (E series) used for the first time with considering its structural aspects can be considered as the most effective countermeasure only for the common geometries of the model piers. The results showed that the combination of different countermeasures would not be an efficient tool for all geometries of model piers.     

人造卫星轨道要素的计算

本文阐述了人造卫星的轨道计算方法。内容包括轨道的形成、分类与要素以及椭圆轨道与圆轨道的设计计算方法。