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1.
We solve the uvbyRI light curves obtained by Wolf (1994) with a CCD photometer. Wolf did not solve the light curves, while particular interest in them stems from the fact that a secondary minimum, which other observers failed to detect, is clearly seen in the byRI light curves. This enables us to consider a new eclipse model in which we hypothesize that the secondary component at primary minimum completely obscures the primary, smaller B star, but, at the same time, the light from a third star is observed. Based on this hypothesis, we computed the brightness of each of the three stars for the six bands by analyzing the depths of the primary and secondary minima. Satisfactory agreement between theoretical and observed light curves was achieved by assuming the following parameters for the stars: effective temperature T 1=17000 K, radius R 1 = 2.5 R ⊙, spectral type Sp1 = B3—B4 for the primary; T 2=5700 K, R 2 = 8.4 R ⊙, Sp2 = G0—G2 for the secondary; and T 3=29000 K, R 3 = 1.0 R ⊙, Sp3=B0 for the third star. In the Hertzsprung-Russell diagram, the first star lies on the zero-age main sequence, the second is on the way from the birthline to the main sequence in the region of giants, and the third falls within the region of hot subdwarfs.  相似文献   

2.
Two CCD spectra of the star BM Ori were obtained with the echelle spectrograph of the 6-m telescope. In one of the spectra, a large proportion of lines are distorted by emission. The emission component is blueshifted by 50 km s?1, suggesting hot-gas outflow from the atmosphere. The equivalent-width ratio of measured lines in the spectra outside and during eclipse is consistent with the assumption that ～2/3 of the primary star’s area is obscured during eclipse, as follows from light curves. Measured line equivalent widths were used to estimate atmospheric parameters of the secondary star, T eff=7300 K, log g=5.2, and microturbulence ξt=6 km s?1, and to determine its chemical composition. The C, Na, Al, Si, S, Ca, Fe, Ni, and Zn abundances are solar, within the error limits. Li, Sc, Ti, V, Cr, Mn, Co, and Y are overabundant, while Mg, Cu, and Ba are underabundant. In general, the secondary is similar in chemical composition to the star V 1016 Ori. Based on the secondary’s mass determined by solving the radial-velocity curve and on log g estimated spectroscopically from iron ionization equilibrium, we calculated its photospheric radius, R 2 = 0.5R ⊙. However, the spectroscopic log g=5.2 disagrees with log g=3.5 calculated from the luminosity and effective temperature and with log g=3.0 calculated from light and radial-velocity curves. If the secondary’s photospheric radius is indeed small; this argues for the hypothesis that the eclipsing body is a dust envelope. The radial velocities measured from the two spectra are systematically higher than those calculated from the radial-velocity curve by +34 and +24 km s?1. It is likely that the secondary’s atmosphere occasionally shrinks.  相似文献   

3.
A series of highly accurate photoelectric observations of the eclipsing binary MZ Lac was obtained with a 48-cm AZT-14 reflector at the Tien-Shan High-Altitude Station of the Sternberg Astronomical Institute from 1985 to 2004 to study its apsidal motion. We constructed a consistent system of physical and geometrical parameters of the components and the binary’s orbit: we determined their masses (M1 = 1.50M⊙, M2 = 1.29M⊙), radii (R1 = 1.86R⊙, R2 = 1.35R⊙), luminosities (L1 = 0.79L⊙, L2 = 0.45L⊙), surface gravities (logg1 = 4.06, logg2 = 4.27), age (t = 1.9 × 109 yr), and the distance to the binary (d = 510 pc). The binary exhibits apsidal motion with the period Uobs = 480 ± 40 yr, while its theoretically expected value is Uth = 450 ± 40 yr. Spectroscopic studies of MZ Lac and calculations of the absolute parameters of the components are required to test our conclusions.  相似文献   

4.
We present the results of our long-term photometric and spectroscopic observations at the Russian–Turkish RTT-150 telescope for the optical counterpart to one of the best-known sources, representatives of the class of fast X-ray transients, IGR J17544-2619. Based on our optical data, we have determined for the first time the orbital and physical parameters of the binary system by the methods of Doppler spectroscopy.We have calculated theoretical spectra of the optical counterpart by applying non- LTE corrections for selected lines and obtained the parameters of the stellar atmosphere (T eff = 33 000 K, log g = 3.85, R = 9.5 R ⊙, and M = 23 M ⊙). The latter suggest that the optical star is not a supergiant as has been thought previously.  相似文献   

5.
New BV light curves of the A-type W UMa star AQ Psc (P = 0.476d) have been observed and are described. A few times of minimum light are obtained and the ephemeris is improved. The light curves are analyzed for the binary parameters with a light curve synthesis method. Combining the results with Lu and Rucinski’s spectroscopic mass ratio we determined the masses and radii of the components: M 1 = 1.69M ⊙, M 2 = 0.38M ⊙, R 1 = 1.77R ⊙, and R 2 = 0.89R ⊙.  相似文献   

6.
Continuous wavelet transform and cross‐wavelet transform have been used to investigate the phase periodicity and synchrony of the monthly mean Wolf (Rz) and group (Rg) sunspot numbers during the period of June 1795 to December 1995. The Schwabe cycle is the only one common period in Rg and Rz, but it is not well‐defined in case of cycles 5–7 of Rg and in case of cycles 5 and 6 of Rz. In fact, the Schwabe period is slightly different in Rg and Rz before cycle 12, but from cycle 12 onwards it is almost the same for the two time series. Asynchrony of the two time series is more obviously seen in cycles 5 and 6 than in the following cycles, and usually more obviously seen around the maximum time of a cycle than during the rest of the cycle. Rg is found to fit Rz better in both amplitudes and peak epoch during the minimum time time of a solar cycle than during the maximum time of the cycle, which should be caused by their different definition, and around the maximum time of a cycle, Rg is usually less than Rz. Asynchrony of Rg and Rz should somewhat agree with different sunspot cycle characteristics exhibited by themselves (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

7.
The physical and geometrical parameters of the individual components of the binary system Hip11253 (HD14874) are estimated. We used the method described in previous papers, which consists in getting the best fit between the entire observational spectral energy distribution of the system and the synthetic ones, created from model atmospheres. The parameters of the individual components of the system are derived as: T eff a = 6030 ± 100 K, T eff b = 4470 ± 130 K, log g a = 4.27 ± 0.13, log g b = 4.04 ± 0.13, R a = 1.22 ± 0.09R⊙, R b = 1.32 ± 0.20R⊙, with the G0 and K4.5 spectral types for the primary and secondary components, respectively. The synthetic magnitudes of both components were calculated using the Johnson-Cousins, Strömgren, and Tycho photometrical systems. Finally the formation and evolution of the system was discussed.  相似文献   

8.
To redetermine the Galactic spiral density wave parameters, we have performed a spectral (Fourier) analysis of the radial velocities for 44 masers with known trigonometric parallaxes, proper motions, and line-of-sight velocities. The masers are distributed in awide range of Galactocentric distances (3.5 kpc < R < 13.2 kpc) and are characterized by a wide scatter of position angles ?? in the Galactic XY plane. This has required an accurate allowance for the dependence of the perturbation phase both on the logarithm of the Galactocentric distances and on the position angles of the objects. To increase the significance of the extraction of periodicities from data series with large gaps, we have proposed and implemented a spectrum reconstruction method based on a generalized maximum entropy method. As a result, we have extracted a periodicity describing a spiral density wave with the following parameters from the maser radial velocities: the perturbation amplitude f R = 7.7 ?1.5 +1.7 km s?1, the perturbation wavelength ?? = 2.2 ?0.1 +0.4 kpc, the pitch angle of the spiral density wave i = ?5 ?0.9° +0.2° , and the phase of the Sun in the spiral density wave ?? ?? = ?147 ?17° +3° .  相似文献   

9.
The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: T eff A = 5350 ± 50 K, T eff B = 4400 ± 50 K, log g A = 4.40 ± 0.05, log g B = 4.68 ± 0.05, R A = 0.95 ± 0.06R ⊙, R B = 0.58 ± 0.06R ⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed.  相似文献   

10.
The following sunspot formation indices are analyzed: the relative sunspot number R z, the normalized sunspot group number R g, and the total sunspot area A. Six empirical formulas are derived to describe the relations among these indices after 1908. The earlier data exhibit systematic deviations from these formulas, which can be attributed to systematic errors of the indices. The Greenwich data on the sunspot total area A and the sunspot group number in 1874–1880 are found to be doubtful. Erroneous data at the beginning of the Greenwich series must spoil the values of the index R g in the XVII–XIX centuries. The Hoyt-Schatten series of R g may be less reliable than the well-known Wolf number series R z.  相似文献   

11.
A stability criterion is given for the equilibrium form of an ideal rotating fluid in the post-Newtonian approximation. This generalizes the known Lyapunov criterion in classical dynamics. The sphere stability is also investigated and it is shown that it is stable only whenR>22.2R g (R is the relativistic sphere radius,R g the Schwarzschild radius).  相似文献   

12.
The first radial velocity curves for V404 And have been obtained. Combined with new light curve data, simultaneous Roche-based light curve analyses have been carried out using the 2003 version of the Wilson-Devinney code. New values for the masses, radii, and luminosities have been obtained: M1 = 0.870 (11) M ʘ, M 2 = 0.706 (9) M ʘ, R1 = 1.10 (13) Rʘ, R2 = 1.37 (13) Rʘ, L1 = 0.75 (7) L ʘ, and L 2 = 0.87 (8) L ʘ. Reference to the sample of close binary stars from Yakut and Eggleton (2005) and the ZAMS indicates that both stars are evolved. Further, the system may have been a classical Algol in the past but with the secondary then contracting, yielding the near semi-contact binary that we have today.  相似文献   

13.
Recently, the estimation of coronal magnetic field using new methods, such as standoff distance method or density compression ratio method has been reported. In the present work, we utilized the density compression ratio of CME-driven shocks for 10 events at 29 different locations in the upper solar corona (10–26R ⊙) and determined the coronal magnetic field for two different adiabatic indices (γ=4/3 and 5/3). In addition, radial dependence of shock parameters in the corona is studied. It is found that the magnetic field estimated in the above range agree with the general trend. In addition, we obtained a radial profile of magnetic field [B(R)=623R ?1.4] in the entire upper corona (3–30R ⊙) by combining the magnetic field estimated by Kim et al. (Astrophys. J. 746:118, 2012) in the range 3–15R ⊙ and that estimated in the present study in the range (10–26R ⊙). The power-law indices are nearly in agreement with recent results of CME-driven shocks reported in the literature. The results are discussed with the comparison of newly reported coronal magnetic field values obtained by different techniques and found that the power-law relation closely follow the literature values.  相似文献   

14.
We have tested the method of determining the solar Galactocentric distance R 0 and Galactic rotation velocity V 0 modified by Sofue et al. using near-solar-circle objects. The motion of objects relative to the local standard of rest has been properly taken into account. We show that when such young objects as star-forming regions or Cepheids are analyzed, allowance for the perturbations produced by the Galactic spiral density wave improves the statistical significance of the estimates. The estimate of R 0 = 7.25 ± 0.32 kpc has been obtained from 19 star-forming regions. The following estimates have been obtained from a sample of 14 Cepheids (with pulsation periods P > 5 d ): R 0 = 7.66 ± 0.36 kpc and V 0 = 267 ± 17 km s?1. We consider the influence of the adopted Oort constant A and the character of stellar proper motions (Hipparcos or UCAC4). The following estimates have been obtained from a sample of 18 Cepheids with stellar proper motions from the UCAC4 catalog: R 0 = 7.64 ± 0.32 kpc and V 0 = 217 ± 11 km s?1.  相似文献   

15.
From the equivalence principle, one gets the strength of the gravitational effect of a mass M on the metric at position r from it. It is proportional to the dimensionless parameter β 2=2GM/rc 2, which normally is ?1. Here G is the gravitational constant, M the mass of the gravitating body, r the position of the metric from the gravitating body and c the speed of light. The seeable universe is the sphere, with center at the observer, having a size such that it shall contain all light emitted within it. For this to occur one can impose that the gravitational effect on the velocity of light at r is zero for the radial component, and non zero for the tangential one. Light is then trapped. The condition is given by the equality R g =2GM/c 2, where R g represents the radius of the seeable universe. It is the gravitational radius of the mass M. The result has been presented elsewhere as the condition for the universe to be treated as a black hole. According to present observations, for the case of our universe taken as flat (k=0), and the equation of state as p=?ρc 2, we prove here from the Einstein’s cosmological equations that the universe is expanding in an accelerated way as t 2, a constant acceleration as has been observed. This implies that the gravitational radius of the universe (at the event horizon) expands as t 2. Taking c as constant, observing the galaxies deep in space this means deep in time as ct, linear. Then, far away galaxies from the observer that we see today will disappear in time as they get out of the distance ct that is <R g . The accelerated expanding vacuum will drag them out of sight. This may be a valid test for the present ideas in cosmology. Previous calculations are here halved by our results.  相似文献   

16.
We present new photometric observations covering eight minima times for the eclipsing binary GSC 1042-2191. The light curves in BVRI colors were analyzed by using WD-code for the system parameters. Eight minima times were obtained from the new observations. The system is found a low mass ratio (q = 0.148), A-type over-contact binary with a fill out parameter of f = 65.01 ± 12.18%. The preliminary absolute dimensions (M1= 1.26 ± 0.06 M⊙, M2 = 0.18 ± 0.06 M⊙, R1 = 1.54 ± 0.20 R⊙, R2 = 0.69 ± 0.01 R⊙, L1 =3.30 ± 0.30 L⊙ and L2 = 0.59 ± 0.20 L⊙) indicate the very much oversized and over-luminous secondary component, by assuming the present luminosity of the secondary is its main sequence luminosity, we predict the original mass is about 0.8 M⊙, this means the present secondary could be transferred and/or lost 77% of its original mass and only its core is left.  相似文献   

17.
Based on kinematic data on masers with known trigonometric parallaxes and measurements of the velocities of HI clouds at tangential points in the inner Galaxy, we have refined the parameters of the Allen-Santillan model Galactic potential and constructed the Galactic rotation curve in a wide range of Galactocentric distances, from 0 to 20 kpc. The circular rotation velocity of the Sun for the adopted Galactocentric distance R 0 = 8 kpc is V 0 = 239 ± 16 km s?1. We have obtained the series of residual tangential, ΔV θ , and radial, V R , velocities for 73 masers. Based on these series, we have determined the parameters of the Galactic spiral density wave satisfying the linear Lin-Shu model using the method of periodogram analysis that we proposed previously. The tangential and radial perturbation amplitudes are f θ = 7.0±1.2 km s?1 and f R = 7.8±0.7 km s?1, respectively, the perturbation wave length is λ = 2.3±0.4 kpc, and the pitch angle of the spiral pattern in a two-armed model is i = ?5.2° ±0.7°. The phase of the Sun ζ ⊙ in the spiral density wave is ?50° ± 15° and ?160° ± 15° from the residual tangential and radial velocities, respectively.  相似文献   

18.
The photometric elements of the eclipsing binary NSV 18773 (HD 99898) have been determined for the first time by analyzing its V-and I-band light curves from the ASAS-2 and ASAS-3 catalogs. Based on these elements and using other published spectroscopic and photometric data, we constructed a consistent system of geometrical and physical parameters for the system that consists of two stars (M 1 = 20M ⊙, Sp1=B0V, R 1 = 5.0R ⊙ and M 2 = 14M ⊙, Sp2 = B1V, R 2 = 6.5R ⊙) in elliptical orbits (P = 5 . d 049, e = 0.365, a = 40.1R ⊙). The distance to the system is d = 3.3 kpc, the interstellar extinction is A V = 2 . m 0, and the age is t = 2.8 × 106 yr. NSV 18773 is a visual binary with components V A = 9 . m 9 and V B = 10 . m 3 separated by 0 . " 8. The third light (L 3 = 0.61) that we found by analyzing the light curves shows that the eclipsing binary is the system’s fainter component B. We confirmed the rapid apsidal motion of the star detected by Otero and Wils (2006) and refined its observed period: U obs = 150 ± 6 yr. Our photometric elements and physical parameters allowed the apsidal parameter $\bar k_2^{obs} = 0.0135(14)$ , which reflects the density distribution along the radii of the component stars, to be determined. Within the error limits, the derived parameter agrees with its theoretically expected value, $\bar k_2^{th} = 0.0119(8)$ , from current evolutionary models of stars of the corresponding masses and ages.  相似文献   

19.
We present the results of our investigation of the geometrical and physical parameters of the W UMa‐type binary V404 Peg from analysis of CCD (BVRI) light curves and radial velocity data. The photometric data were obtained during 2010 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously by using the well‐known Wilson‐Devinney (2007 revision) code to obtain absolute and geometrical parameters. Our solution indicates that V404 Peg is an A‐type overcontact binary with a mass ratio of q = 0.243 and an overcontact degree of f = 32.1 %. Combining our light curves with the radial velocity curves from Maciejewski & Ligeza (2004), we determined the absolute parameters of this system as follows: a = 2.672 R⊙, M1 = 1.175 M⊙, M2 = 0.286 M⊙, R1 = 1.346 R⊙, and R2 = 0.710 R⊙. Finally, we discuss the evolutionary condition of the system (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

20.
Highly accurate W BV R photometric measurements of the eclipsing binary HP Aur were performed in 2002–2003 with the 48-cm AZT-14 reflector at the Tien-Shan High-Altitude Observatory to determine the rate of apsidal motion. A consistent system of physical and geometrical parameters of the components and the binary as a whole has been constructed for the first time by analyzing these new measurements together with other published data: we determined their radii (R1 = 1.05R⊙, R2 = 0.82R⊙) and luminosities (L1 = 1.10L⊙, L2 = 0.46L⊙), spectral types (G2V + G8V) and surface gravities (log g1 = 4.38, log g2 = 4.51), age (t = 9.5 × 109 yr), and the distance to the binary (d = 197 pc). We detected an ultraviolet excess in the spectra of both components, \(\Delta (W - B) \simeq - 0\mathop .\limits^m 25\), that is probably attributable to a metal deficiency in the atmospheres of these stars. In this system of two solar-type stars, we found a third body with the mass M3 sin i 3 3 = 0.17M⊙ that revolved with the period P3 = 13.7 yr around the eclipsing binary in a highly eccentric elliptical orbit: e3 = 0.70 and A3 sin i3 ? 7 AU. The orbit of the eclipsing binary itself was shown to be also elliptical, but with a low eccentricity (e = 0.0025(5)), while apsidal motion with a period Uobs > 80 yr was observed at a theoretically expected period Uth ≈ 92 yr. At least 20 to 30 more years of photoelectric measurements of this star will be required to reliably determine Uobs.  相似文献   

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