Spectroscopic study of the eclipsing binary V 367 Cygni

Seventeen coudé spectrograms (dispersion 20 A mm^–1) of the Lyrae-type eclipsing binary V 367 Cygni (P=18.6 d) have been studied. The observations were made at the Haute Provence Observatory during a period of almost two years (May 1973–March 1975). An anomalous behavior for the radial velocities of the spectrograms taken during one cycle (406) was observed; it is suggested that gas eruption under form of prominences may explain it. The spectrum is dominated by shell lines very similar to those present in the spectrum of the supergiant A9 Ia Aurigae. The underlying stellar spectrum is classified as A5 I on the basis of the intensity of the sole clearly visible stellar line, 4481 MgII, of the wings of the stellar Balmer lines, and an estimate of the intensity of the stellarK line. The radial velocity curves for the shell lines of CaII, HI, metallic ions and neutral iron, as well as the phase dependence of the microturbulence, indicate stratification in the shell.     

New period study of the eclipsing binary V865 Cygni

Several new precise times of minima, based on CCD observations, have been secured for the relatively seldom studied eclipsing binary V865 Cyg (P=0^d.365 days). Its O–C diagram was analysed and new light elements are given. We showed that there is probably no parabolic period increase in V865 Cyg. Instead, a single abrupt period increase can be distinguished in the O–C diagram.     

Photometric analysis of the eclipsing binary V1425 Cygni

Photoelectric B and V light curves of the eclipsing binary V1425 Cygni were analyzed by the method of Wilson-Devinney. The system was found to be a semi-detached binary where the secondary component (less massive and cooler) fills its Roche lobe.     

Photoelectric photometry of the eclipsing binary V1425 Cygni

Photoelectric differentialB andV magnitudes of the eclipsing binary V1425 Cygni are presented yielding the complete photoelectric light curve of this relatively bright system. The improved light elements are calculated using the least-squares method.     

Light curve variations of the eclipsing binary V367 Cygni

The long-period eclipsing binary star V367 Cygni has been observed photoelectrically in two colours,B andV, in 1984, 1985, and 1986. These new light curves of the system have been discussed and compared for the light-variability with the earlier ones presented by Heiser (1962). Using some of the previously published photoelectric light curves and the present ones, several primary minima times have been derived to calculate the light elements. Any attempt to obtain a photometric solution of the binary is so complicated by the peculiar nature of the light curve caused by the presence of the circumstellar matter in the system. Despite this difficulty, however, some approaches are being carried out to solve the light curves which will be discussed shortly.     

The first photometric study of semi-detached eclipsing binary V504 Cyg

In this paper, we analyze photometry of V504 Cyg semi-detached binary system. For this purpose, after taking the photometric data, primary and secondary minimum and new epoch were calculated. The period of system is found to be 0.3516916 day. Analysis of light curve was performed by PHOEBE software which uses last version of Wilson–Devinney code. 3D model of the system is worked out using Binary Maker software. The O’Connell effect in the light curve is observed and an accurate model of this system is presented by introducing four spots on the components.     

A photometric study of the short-period eclipsing binary BW Eridani

UBV observations of the short-period eclipsing binary BW Eri are reported and analyzed. The photometric parameters are determined. BW Eri is a detached or semidetached system.     

A photometric study of the eclipsing binary 68 u Her

The aim of this paper is to present and study the light curves (B andV) of the eclipsing binary 68 u Her from the photometric observations made at Al-Battani Observatory.New photometric elements have been obtained by a Fourier analysis of the light changes in the frequency-domain.     

The spectroscopic orbit of the short period eclipsing binary V 836 Cygni

Spectroscopic elements of the single-lined spectroscopic binary V 836 Cyg are presented.     

First photometric study of the eclipsing binary PS Persei

CCD photometric observations of the eclipsing binary PS Persei (PS Per) were obtained on two consecutive days in 2009.The 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R bands.It is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche lobe.The mass ratio of q=0.518 and the orbital inclination of i=89.86° are obtained.In addition,based on all available times of primary light...     

The first photometric analysis of the near-contact binary star V370 Cygni

The first complete CCD light curves of the eclipsing binary system V370 Cygni have been obtained in the B, V, R and I filters during 5 consecutive nights in 2005 at Kryoneri Observatory, Greece. These curves were analyzed with the Wilson–Devinney program in order to determine the geometrical and physical parameters of the system. The analysis indicates a semi-detached configuration and a mildly evolved state of the system.      

Comprehensive photometric study of the eclipsing binary AW UMa

Due to its extreme mass ratio, the system AW UMa is considered as one of the most interesting contact binaries. In the present paper, a total of 1289 observations in VRI band were carried out from on 2006 March 7, 8, and 9 at Piszkesteto, Mountain Station of the Konkoly observatory (Hungary). VRI light curves were constructed and a photometric solution of these light curves was obtained by means of Willson-Devinney code. The results show that the primary component is more massive and hotter than the primary component by ～140 K. A secular period decrease with a rate dP/dE=2.436×10^?10 day/cycle was detected. Based on the physical parameters of the system, we investigate the evolutionary state of the components. The primary component is above the zero age main sequence (ZAMS) track, while the secondary component has a larger radius and luminosity than expected from its ZAMS mass.     

Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg

New multi-color BV RcIcphotometric observations are presented for the W UMa type eclipsing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 yr,including CCD data to construct the O-C curve, and performed detailed O-C analysis. The O-C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic variation exist. The period is decreasing at a rate of P =-1.04(±0.18) × 10~(-10) d cycle~(-1) and, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P_3= 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002) d may be explained by magnetic activity of one or both components or the light travel time effect caused by a distant third companion with M_3(i′= 90?) = 0.511 M_⊙.     

A multicolor photometric study of the neglected eclipsing binary FT Ursae Majoris

The multicolor photometric observations of the neglected eclipsing binary FT Ursae Majoris (FT UMa) were obtained in 2010. The 2003 version of the Wilson-Devinney code was used to analyze the light curves in the B, V and R bands simultaneously. Based on the spectroscopic mass ratio q = 0.984 published by Pribulla et al., it is found that FT UMa is an evolved contact binary with a contact degree of 15.3%. The low amplitude of light variations, ～ 0.15 mag, arises mainly from a moderately low inclination angle...     

A photometric and spectroscopic study of the short-period eclipsing binary BV Eridani

UBV observations of the short-period eclipsing binary BV Eri are reported and analyzed. The radial velocity curve is given. The system shows a light curve distortion, making an analysis difficult. The secondary fills its critical Roche lobe. The system seems to be in an interesting evolutionary.     

A comprehensive photometric study of the Algol-type eclipsing binary: BG Pegasi

This study presents new photometric observations of classical Algol type binary BG Peg with a δ Scuti component. The light curve modeling was provided with the physical parameters of the component stars in the BG Peg system for the first time. After modeling light curves in B and V filters, the eclipse and proximity effects were removed from the light curve to analyze intrinsic variations caused by the hotter component of the system. Frequency analysis of the residuals light represents the multi-mode pulsation of the more massive component of the BG Peg system at periods of 0.039 and 0.047 days. Two frequencies could be associated with non-radial (l = 2) modes. The total amplitude of the pulsational variability in the V light curve was found to be about 0.045 mag. The long-term orbital period variation of the system was also investigated for the first time. The O–C analysis indicates periodic variation superimposed on a downward parabola. The secular period variation means that the orbital period of the system is decreasing at a rate of ?5.5 seconds per century, probably due to the magnetic activity of the cooler component. The tilted sinusoidal O–C variation may be caused by the gravitational effect of an unseen component around the system.     

First photometric study of two eclipsing binary star systems: V523 And and V543 And

Detailed photometric analysis of V523 And and V543 And from the Wide Angle Search for Planets survey is presented for the first time. It was found that while V523 And is a detached binary, V543 And is a semi-detached binary star system. The adopted masses and radii for the primary and secondary components are $M_1=0.77\pm 0.08$ M${}_{\odot }$, $R_1=0.87\pm 0.08$ R${}_{\odot }$ and $M_2=0.50\pm 0.12$ M${}_{\odot }$, $R_2=0.77\pm 0.17$ R${}_{\odot }$ for V523 And; and $M_1=1.59\pm 0.16$ M${}_{\odot }$, $R_1=1.46\pm 0.09$ R${}_{\odot }$ and $M_2=0.58\pm 0.17$ M${}_{\odot }$, $R_2=1.66\pm 0.22$ R${}_{\odot }$ for V543 And. Orbital period variations of the systems were analyzed using the O-C method. The O-C change of V523 And is discussed in terms of the magnetic activity cycle of one or both components and light travel time effect (LTTE) due to a third body in the system. Among these mechanisms, LTTE seems to be the most appropriate mechanism to explain the O-C variation of the system since the quadrupole moments of the primary and secondary components ($\Delta Q$) were found to be in the order of $10^{49}$ g cm${}^2$. The O-C diagram of V543 And shows a downward parabolic trend, which suggests a secular period decrease with a rate of $0.080\pm 0.012$ s/year. The parabolic O-C variation of V543 And was interpreted in terms of the non-conservative mass transfer mechanism. According to this scenario, the range of possible values of the mass gain rate (${\dot{M}}_1$) of the primary component of V543 And as well as the mass-loss rate ($\dot{M}$) of the system were found to be $10^{-5}$–$10^{-11}$ M${}_{\odot }$/year and $10^{-6}$–$10^{-8}$ M${}_{\odot }$/year, respectively.     

KR Cygni: a near-contact eclipsing binary?

In this study we present photometric observations of the eclipsing binary KR Cyg made in 1999 and 2000. The observations of the eclipsing binary KR Cyg have been carried out in B, V and R colours at the Ege University Observatory. A new seasonal light curves are presented. New times of minima and ephemerides are given. Based on a statistical analysis of the times of minima obtained by photoelectric photometry, the orbital period of the system is found to be constant. The photometric mass ratio of the system is well determined. The corresponding light curves were analyzed by the Wilson-Devinney code. This revised version was published online in July 2006 with corrections to the Cover Date.