UBVRI Photometry and Polarimetry of the Eclipsing Binary RY Per

Results are presented from multicolor photometric and polarimetric studies of the eclipsing binary RY Per during 2001-2003. Light curves in the UBVRI bands are shown. An analysis of the variations in the linear polarization makes it possible to separate it into interstellar and intrinsic components. The degree of intrinsic polarization of the system away from the eclipse attains a maximum (0.23%) in the B band and falls off rapidly with increasing wavelength. This dependence is indicative of the existence of optically thick gas in the system. An analysis of the polarimetric data also shows that: the total mass of optically thin gas in the system is about 2·10^-10 M , while the total mass of the shell must be several times that; and, the inclination of the orbital plane of the binary system relative to the galactic plane is 4° or 18°.     

Revised Orbital Parameters of Beaming Eclipsing Binary System HV Cnc from Kepler Photometry

High precision photometry gathered from Kepler database and radial velocity measurements of the HV Cnc system found in the literature were simultaneously analyzed by the Wilson-Devinney (WD) code to better understand system parameters. Some physical quantities needed by the WD code in iterations, such as limb darkening coefficients, Kurucz’s model atmospheres, and blackbody approach were considered by using precise transmission curves of each Kepler channel. Therefore, we obtained a set of revised system parameters relative to the previous solution of Gökay et al. (2013) in which the results were based on the photometry of 2MASS archival data. In the present solution, we recognized a low amplitude (Δm_Kepler ∼ 0.^m001) brightening at the primary quadrature of the light curve. This excess light is modelled by considering a combination of ellipsoidality, reflection, and Doppler beaming effects. Consequently, we propose the system as a new candidate of Doppler beaming binary.According to the absolute parameters of the primary component, we discussed the evolutionary status of the blue straggler component in the system. Furthermore, on the basis of absolute parameters, distance estimation to the system is 827 ± 20 pc which supports that HV Cnc is very likely a member of M67 cluster.     

Eccentric Eclipsing Binary YY Sagittarii

Seven new precise times of minimum light have been gathered for the triple eccentric eclipsing binary YY Sgr (P = 2^d.63, e = 0.16). Its O--C diagram is presented and improved elements of the apsidal motion and the light-time effect are given. We found a new short period of the third body of about 18.5 years in an eccentric orbit (e ₃ ≃ 0.4).     

Radial Velocity and Light Curve Analysis of the Eclipsing Binary Nn Vir

The eclipsing binary NN Vir is a short period system showing an EW-type light curve. Photometric observations of NN Vir were done by Gomez–Ferrellad and Garcia–Melendo (1997) at Esteve Duran Observatory. The first spectroscopic observations of this system were obtained by Rucinski and Lu (1999). The radial velocity and light curves analysis was made with the latest version of the Wilson program (1998), and the geometric and physical elements of the system are derived. From the simultaneous solutions of the system, we determined the masses and radii of the components: 1.89 M _⊙ and 1.65 R _⊙ for the primary component; 0.93 M _⊙ and 1.23 R _⊙ for the secondary component. We estimated effective temperatures of 7030 K for the primary and 6977 K for the secondary component.     

Updated UBV Light-Curve and Period Analysis of Eclipsing Binary HS Herculis

UBV light-curves of the eclipsing binary HS Herculis, obtained in 2002–2003 observational seasons, were analysed with Wilson-Devinney computer code. New absolute dimensions of the system were calculated using the results of the light-curve analysis. Period variation of the system was also investigated. Several new times of minima have been secured for this problematic system. An apsidal motion with a period of 80.7 years was confirmed and a third body in a pretty eccentric orbit (e ₃ = 0.90 ± 0.08) with a period of 85.4 years was found. The corresponding internal structure constants of the binary system, log k ₂, and the mass of the third body were derived.     

A New Light Curve Analysis of the Eclipsing Binary SX Aur

Using WOOD 's (1972) model, we have analysed BONDARENKO 's (1974) two-colour photoelectric observations – till now unsolved – of the eclipsing binary SX Aur. Our photometric solutions turn out to be in substantial agreement with those derived by CHAMBLISS and LEUNG (1979); they confirm that SX Aur is a post-mass exchange (case A) semi-detached system.     

Modeling the Eclipsing Binary System VW Cygni

Five color UBVRI photometric and polarimetric measurements of the eclipsing binary VW Cyg are reported. It is shown that in the primary minimum the luminosity is attenuated (at short wavelengths) even after passage of the second contact. This fact is interpreted as evidence of gaseous structures in the system. The exchange of matter among the system components is also confirmed by the O-C curve constructed from data covering nearly a hundred years. Polarimetric analysis makes it possible to isolate the intrinsic (P=0.030±0.02) and interstellar components of the polarization. The UBVRI light curves of VW Cyg have been resolved. This was done using an algorithm for synthesizing theoretical light curves in the Roche model. Good agreement was obtained between the theoretical curves and observations in the V, R, and I bands, but the observed minimum depths in the U and B bands exceed the theoretical values. This appears to be caused by gas flows in the system.     

Spectroscopic Orbit of the Eclipsing Binary AI Draconis

New radial velocity measurements of the Algol-type eclipsing binary AI Dra, based on Reticon observations, are presented. The velocity measures themselves are based on fitting theoretical profiles, generated by a physical model of the binary, to the observed cross-correlation function (ccf). Such profiles match this function very well, much better in fact that Gaussian profiles which are generally used. Measuring the ccf's with Gaussian profiles yields following results: m_p sin³ i=2.55± 0.05m_⊙, m_s sin³ i = 1.14 ± 0.03m_⊙, (a_p + a_s) sin i=7.34 ±0.05R_⊙, and m_p/m_s =2.23± 0.05. Where as measuring the ccf's with theoretical profiles yields a mass ratio of 2.33 and following results: m_p sin³ i=2.84± 0.05m_⊙, m_s sin³ i=1.22 ± 0.03m_⊙, (a_p +a_s) sin i=7.56± 0.05R_⊙. The system comprising a semi-detached configuration. From the solution of a previously published light curved and combining it's results with the spectroscopic orbit, one can lead to the following physical parameters: m_p =2.99m_⊙, m_s =1.28m_⊙, > T_p < =9600 K, > T_s < =5400 K, > R_p < =2.35R_⊙, > R_s < =2.12R_⊙. The system comprising an AO primary and a secondary of G2 spectral type. This revised version was published online in July 2006 with corrections to the Cover Date.     

Eclipsing Binary Stars in Nearby Galaxies

We briefly discuss the survey programme we are conducting to detect eclipsing binaries in local group galaxies. Some lightcurves from studies of M31, IC 1613 and NGC 6822 are presented along with details of future work.     

Photometric Mass Ratios of Eclipsing Binary Stars

Following a brief history of measurement of eclipsing binary mass ratios from light curves, we show that photometric mass ratios for overcontact and semi-detached binaries are reliable because the relative stellar radii, R/a, are accurately measured and not, as commonly claimed, because of information in the light variation outside eclipse. We explore the accuracy of photometric mass ratios by solving synthetic data of typical precisions for a semi-detached and an overcontact binary for orbital inclinations from 89^∘ down into the partial eclipse range.     

A Detached Binary System V505 Persei

The UBV photometry of a detached F-type eclipsing binary V505 Persei is presented. The light curve solution by a simple spherical model combined with the radial velocity data from two high resolution spectra by Marschall et al. (1990) reveals that the system is formed with two identical component stars of M 1.2 M in the main sequence close to ZAMS in evolution. They should have about solar metallicity (z 0.017). The isochrones with solar metallicity by Van denBerg (1985) yield an age of about (2.2± 0.5) × 10⁹ yr for the system. The distance of the system should be about 60 pc.     

EPIC 202060577的双星解轨和物理参数研究

EPIC 202060577是一个包含B型子星的食双星系统.根据K2测光数据获得了45个次极小时刻,确定其轨道周期为1.019648 d并给出了历元公式.基于大天区面积多目标光纤光谱望远镜(Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST1,又称郭守敬望远镜)的光谱数据,使用ROTFIT程序获得了目标系统的主星光谱型、有效温度、金属丰度与表面重力加速度,并计算得到了视向速度曲线.通过PHOEBE (Physics Of Eclipsing Binaries)建模程序和emcee (Affine Invariant Markov chain Monte Carlo Ensemble Sampler)拟合程序,对EPIC 202060577进行了轨道求解并分析了RossiterMcLaughlin效应对视向速度曲线的影响.最终结果表明EPIC 202060577是一个质量比q=0.11的分离结构食双星系统(q=M2/M1, M1、M2分别为主星和伴星质量),主星的光谱型为B2/3,主星和伴星的质量、半径和有效温度分别为M1=12.56M⊙和M2=1.39M⊙,R1=4.58Rsun和R2=1.85Rsun, T1=18979 K和T2=8710 K, M⊙和Rsun分别为太阳质量和半径.根据所获得的物理参数,对EPIC 202060577的演化阶段进行了讨论.     

Photometric Elements of the Eclipsing Binary AZ Vir

Using WOOD 's (1972) model we have analyzed MEINUNGER 's (1977) B and V photoelectric light curves – as yet unsolved–of the W UMa-type eclipsing binary AZ Vir, for which no photometric elements have as yet been determined. Our results describe AZ Vir as a contact pair in which the star eclipsed at the deeper minimum is smaller than its companion. AZ Vir appears to conform to the general properties of the W-type subclass of W UMa systems.     

Photometric Investigation of the Eclipsing Binary Star KN Per

We used the Behlen observatory 0.76 m telescope and the CCD photometer to secure 689 observation of the eclipsing binary star KN Per. The observations were made on 8 nights during 1993 and 1994 with V and R bandpass filters. From 7 determinations of eclipse timings of minimum (V&R together), we have determined a new epoch and an orbital period of 0.8664604 days. The published spectral classification is A9. The 1993 version of the Wilson-Devinney model gave the photometric solutions. The adopted solution indicates that KN Per is a W UMa type contact binary. The mass ratio, q = (m₂/m₁, where star 1 eclipses at the primary minimum) = 0.23 suggests that KN Per is a W UMa system with A-type configuration. The secondary minimum shows a total eclipse. The asymmetry in the light curve is fitted with a cold spot on the secondary component of the system. The luminosity difference between the components is very large KN Per therefore, is most likely a single line spectroscopic binary. We recommend spectroscopic study of this system. Generally contact systems of spectral type A9 have periods ranging from 0.4 to 0.6 days. KN Per has considerably longer period and thus appears to be an evolved contact system with case B mass transfer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Photometric Solution of the Eclipsing Binary V351 Pegasi

BVR light curves of the recently discovered eclipsing binary V351 Peg were studied to derive the preliminary physical parameters of the system. The light curves were obtained at the TüBİTAK* – Turkish National Observatory (TUG) during three nights in August, 2003. The solutions were made using Djurašević’s inverse problem method. V351 Peg is a system in an overcontact configuration (f _over∼ 21 %) with a relatively small temperature difference between the components ΔT ≈ 20 K. The results suggest a significant mass and energy transfer from the more massive primary onto the less massive secondary. The hot area on the less massive star, near the neck region, can be considered as a consequence of this mass and energy exchange between the components through the connecting neck of the common envelope. TüBİTAK: The Scientific and Technical Research Council of Turkey.     

Photometric Study of Eclipsing Binary U Sagittae

New UBV photometry of Algol type binary star U Sge obtained during 1993 are presented, analyzed, and discussed. Wilson-Devinney code was employed to analyze the light curves. Absolute dimensions of the system were obtained, and positions of both components on H-R diagram were specified. Finally through color curve analysis absolute visual magnitudes were determined.     

Photometric Analysis and Period Investigation of the EW Type Eclipsing Binary V441 Lac

Four color light curves of the EW type eclipsing binary V441 Lac were presented and analyzed by the W–D code. It is found that V441 Lac is an extremely low mass ratio (q = 0.093±0.001) semi-detached binary with the less massive secondary component filling the inner Roche lobe. Two dark spots on the primary component were introduced to explain the asymmetric light curves. By analyzing all times of light minimum, we determined that the orbital period of V441 Lac is continuously increasing at a rate of dP/dt = 5.874(±0.007) × 10^?7 d yr^?1. The semi-detached Algol type configuration of V441 Lac is possibly formed by a contact configuration destroyed shallow contact binary due to mass transfer from the less massive component to the more massive one predicted by the thermal relaxation oscillation theory.     

UBV Photometric Study of the Eclipsing Binary DM Delphini

The near-contact system DM Del with an A2V primary and a G8 secondary was observed in U, B and V wavelengths in July 1998. A new seasonal light curve is presented and a new observed time of minimum is given. The unperturbed part of the light curve was used to determine some basic parameters of the system with the Wilson-Devinney code, some of which were kept fixed for spot modelling of the light curves. A simple spot distribution was determined, based on a model with two cool spots on the surface of the secondary. Absolute elements were calculated and the evolutionary status was determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Light Curve Synthesis for the Eclipsing Binary BB Peg

Using Wood's (1972) model we have reanalyzed Cerruti-Sola and Scaltriti's (1980) photoelectric observations of the eclipsing binary BB Peg. Our photometric elements, which turn out to be considerably different from the earlier preliminary results, describe BB Peg as a contact system, in which the component eclipsed at the deeper minimum is smaller than its companion. BB Peg appears to conform to the general properties of the W-type subclass of W UMa systems.