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A new catalogue of eclipsing binary stars with eccentric orbits
(Blackwell Publishing, 2007) Bulut, I.; Demircan, O.
A new catalogue of eclipsing binary stars with eccentric orbits is presented. The catalogue lists the physical parameters (including apsidal motion parameters) of 124 eclipsing binaries with eccentric orbits. In addition, the catalogue also contains a list of 150 candidate systems, about which not much is known at present.
Absolute dimensions and apsidal motion of the eccentric binary V731 Cephei
(Oxford Univ Press, 2008) Bakis, V.; Zejda, M.; Bulut, I.; Wolf, M.; Bilir, S.; Bakis, H.; Demircan, O.
A detailed analysis of new and existing photometric, spectroscopic and spatial distribution data of the eccentric binary V731 Cep was performed. Spectroscopic orbital elements of the system were obtained by means of cross-correlation technique. According to the solution of radial velocities with UBVRc and I-c light curves, V731 Cep consists of two main-sequence stars with masses M-1 = 2.577 (0.098) M-circle dot, M-2 = 2.017 (0.084) M-circle dot, radii R-1 = 1.823 (0.030) R-circle dot, R-2 = 1.717 (0.025) R-circle dot and temperatures T-eff1 = 10700 (200) K, T-eff2 = 9265 (220) K separated from each other by a = 23.27 (0.29) R-circle dot in an orbit with inclination of 88 degrees.70 (0.03). Analysis of the O-C residuals yielded a rather long apsidal motion period of U = 10000 (2500) yr compared to the observational history of the system. The relativistic contribution to the observed rates of apsidal motion for V731 Cep is significant (76 per cent). The combination of the absolute dimensions and the apsidal motion properties of the system yielded consistent observed internal structure parameter (log (k) over bar (2,obs) = -2.36) compared to the theory ( log (k) over bar (2,theo) = -2.32). Evolutionary investigation of the binary by two methods (Bayesian and evolutionary tracks) shows that the system is t = 133(26) Myr old and has a metallicity of [M/H] = -0.04(0.02) dex. The similarities in the spatial distribution and evolutionary properties of V731 Cep with the nearby (rho similar to 3 degrees.9) open cluster NGC 7762 suggest that V731 Cep could have been evaporated from NGC 7762.
Analysis of light curves and apsidal motion of neglected southern eclipsing binary V399 Pup
(Elsevier Science Bv, 2014) Bulut, I.; Bulut, A.; Cicek, C.
In this study, the Hipparcos and ASAS light curves of the eclipsing binary V399 Pup have been analyzed using the Wilson-Devinney program. The light curve analyses have found that V399 Pup is a detached binary system with eccentric orbit. The apsidal motion parameters of the system have been obtained from the O-C curve analyses. The system has been revealed to have an orbital eccentricity of e = 0.145 +/- 0.006, the apsidal motion rate has been obtained omega = 0.0385 +/- 0.0069 deg cycle(-1), and it corresponds to an apsidal motion period of U = 100.2 +/- 18.0 years. (C) 2014 Elsevier B.V. All rights reserved.
Apsidal motion and photometric elements of the eccentric eclipsing binary KL CMa
(Elsevier Science Bv, 2008) Bulut, I.
The Hipparcos and ASAS light curves of the recently discovered eccentric orbit binary KL CMa were analyzed by using the Wilson-Devinney program. The analysis of the light curves and all available minimum times have revealed that the system is detached, with the orbital eccentricity e = 0.131 +/- 0.007, the rate of change of the longitude of periastron (omega) over dot = 0.037 +/- 0.014 degrees cycle(-1), corresponding to an apsidal motion period of U = 46.9 +/- 17.7 yr. The apsidal motion of the system has been confirmed by the significant difference on the longitude of the periastron (omega) obtained from two light curves (Hipparcos and ASAS) in two different epochs. Preliminary absolute parameters of the components have been computed taking into account the result of light curves analysis. (C) 2007 Elsevier B.V. All rights reserved.
Apsidal motion elements of three eccentric eclipsing binaries: V397 Cep, V493 Car and BW Aqr
(Elsevier Science Bv, 2009) Bulut, I.
The apsidal motion analysis of the eccentric eclipsing binaries: V397 Cep, V493 Car and BW Aqr have been presented. The method described by Lacy (1992) [Lacy, C.H S.. 1992. AJ 104, 2213] has been used for the apsidal motion analysis. The apsidal motion periods have been found to be 174.2 +/- 1.4, 277.3 +/- 21.3 and 7195 +/- 174 years for V397 Cep, V493 Car and BW Aqr, respectively. (C) 2009 Elsevier B.V. All rights reserved.
Apsidal Motion in Eclipsing Binaries: FT Ori and MZ Lac
(Amer Inst Physics, 2016) Bulut, A.; Bulut, I.; Cicek, C.; Erdem, A.
In this study, the apsidal motion analysis of two eccentric eclipsing binaries, FT Ori (P = 3.150 days, e = 0.397) and MZ Lac (P = 3.158 days, e = 0.399), have been presented. Their O - C diagrams were studied using all reliable times of minima found in the literature and new values for the elements of the apsidal motion for two systems have been computed. We found long periods of apsidal motion of 538 +/- 12 years and 424 +/- 6 years for FT Ori and MZ Lac, respectively.
Apsidal Motion in Eclipsing Binary GG Orionis
(Amer Inst Physics, 2016) Yilan, E.; Bulut, I.
The study of apsidal motion in binary stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric eclipsing binary GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Gimenez and Garcia-Pelayo (1983) has been used for the apsidal motion analysis.
Apsidal Motion of Two Eclipsing Binaries: V796 Cyg and V2783 Ori
(Amer Inst Physics, 2017) Bulut, A.; Bulut, I.; Cicek, C.; Erdem, A.
In this study, the orbital period variations of two eclipsing binary systems showing apsidal motion were studied. Their O - C diagrams were analysed using all reliable eclipse timings and the elements of apsidal motion of two systems were improved. We found periods of apsidal motion of V796 Cyg and V2783 Ori to be 32.7 +/- 0.2 years and 415 +/- 50 years, respectively.
BVR Photometric Analysis of GSC 4277-0586 and GSC 3152-1202
(Copernicus Foundation Polish Astronomy, 2015) Bulut, I.; Bulut, A.
A detailed light curve analysis of the newly discovered eccentric orbit eclipsing binaries GSC 4277-0586 and GSC 3152-1202 are presented for the fist time. For both systems, the B, V and R light curves were secured and also new minima times have been derived. The analysis was made using the Wilson-Devinney program. The absolute dimensions were calculated using mass-luminosity relation for main sequence stars. The O - C diagram of GSC 3152-1202 was also analyzed using all reliable times of minima and the elements of apsidal motion were computed. The apsidal motion period has been found to be 36.6 perpendicular to 9.8 years.
First ground-based photometry and light-curve analysis of the eccentric eclipsing binary V744 Cas
(Wiley-V C H Verlag Gmbh, 2006) Bulut, I.; Cicek, C.; Erdem, A.; Bakis, V.; Demircan, O.; Degirmenci, O. L.
The first ground-based BVR photometric observations of the recently discovered eclipsing binary V744 Cas are presented. From these measurements, timings for two primary and one secondary minima have been calculated. The light curves of the system were analyzed by using the Wilson-Devinney program. The analysis shows that the system is detached with two similar components of spectral type A2V, and the orbit is eccentric (e = 0.0662 +/- 0.0005). The longitude of the periastron (w) was found significantly different for two different light curves (ours and that of Hipparcos), which is strongly suggestive of an apsidal motion with a period of about 425 +/- 68 yr. This makes V744 Cas an important candidate for studies of apsidal motions. The first estimate of the absolute dimensions place the system close to the terminal age of the main sequence (TAMS) in the HR diagram. The distance from the spectroscopic parallax (d = 740 +/- 10 pc) was found to be slightly larger than the Hipparcos distance of d = 610 +/- 400 pc. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
First photometric study of the W UMa system GSC 1042-2191
(Elsevier Science Bv, 2016) Bulut, A.; Bulut, I.; Demircan, O.
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 (M-1= 1.26 +/- 0.06 M-circle dot, M-2 = 0.18 +/- 0.06 M-circle dot, R-1 = 1.54 +/- 0.20 R (circle dot), R-2 = 0.69 +/- 0.01 R-circle dot, L-1 =3.30 +/- 0.30 L-circle dot and L-2 = 0.59 +/- 0.20 L-circle dot) 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-circle dot, this means the present secondary could be transferred and/or lost 77% of its original mass and only its core is left. (C) 2015 Elsevier B.V. All rights reserved.
Light curve analysis of a new W UMa system GSC 3581-1856
(Elsevier Science Bv, 2018) Bulut, I.; Bulut, A.; Gunes, M.; Demircan, O.
New BVRI photometric observations covering seven minima times for the eclipsing binary GSC 3581-1856 were presented. The light curves in BVRI colours were analysed by using PHOEBE code for the system parameters. New minima times were used in revising the light elements. The system is found a W-type contact binary with mass ratio of q = 1.3362 +/- 0.0042 and a fill out parameter of f = 16.89 +/- 3.17%. The smaller and less massive component was found hotter component (T-1 similar or equal to 5590 K). Lower temperature (T-2 = 5295 K) of the mass accreting more massive component is probably due to a disk or envelope around this star. The original temperature of the more massive secondary component would be at least T-2 similar or equal to 5590K. The preliminary absolute dimensions (M-1 = 0.78 +/- 0.01 M-circle dot, M-2 = 1.05 +/- 0.01 M-circle dot, R-1 = 0.92 +/- 0.10 R-circle dot, R-2 = 1.05 +/- 0.20 R-circle dot, L-1 = 0.86 +/- 0.20 L-circle dot and L-2 = 1.00 +/- 0.20 L-circle dot) indicate a relatively young marginal contact binary for GSC 3581-1856 system. The present luminosity of the less massive but hotter component would be not much different from its main sequence luminosity, and thus its original mass was estimated to be slightly more than one solar mass. This means it could be transferred and/or lost about 30% of its original mass which place the system in relatively young system in contact phase. (C) 2017 Elsevier B.V. All rights reserved.
Light Curve Analysis of Southern Eclipsing Binary EM Car
(Amer Inst Physics, 2017) Cicek, C.; Bulut, I.; Bulut, A.
In this study, ASAS light curve of the eclipsing binary EM Car (Sp = O8V, P = 3.4 days) has been analyzed using the Wilson-Devinney method. The light curve analyses have found that EM Car is a detached eclipsing binary system with small eccentric orbit
Light curve, analyses of new eclipsing binary systems with eccentric orbits
(Elsevier Science Bv, 2008) Bulut, I.; Demircan, O.
A photometric study of seven new eclipsing binary systems with eccentric orbits, namely, V466 Car, V493 Car, V529 Car, MN TrA, V398 Lac, V402 Lac and V821 Cas, is presented. The photometric data analyzed were taken from the Hipparcos database. The secondary minima in all systems were shifted by different amounts from the phase 0.5 giving clear evidence of their eccentric orbits. The EBOP computer program based upon models by Nelson et al. [Popper, D.M., Etzel, P.E., 1981. AJ 86, 102] was used in the analysis of the photometric data to deduce the orbital geometry in space and the relative sizes and luminosities of the component stars. (C) 2007 Elsevier B.V. All rights reserved.
Light-Time Effect in Two Eclipsing Binaries: NO Vul and EW Lyr
(Amer Inst Physics, 2017) Bulut, A.; Bulut, I.; Cicek, C.; Erdem, A.
In this study, orbital period variations of two eclipsing binary systems (NO Vul and EW Lyr) were discussed. Possible light time effects due to third bodies in these systems were re-examined. The mass function and orbital period of hypothetical third bodies were calculated to be 0.000627 +/- 1.000003 M-circle dot, 26.17 +/- 0.05 years and 0.12682 +/- 0.00003 M-circle dot, 77.23 +/- 0.72 years for NO Vul and EW Lyr, respectively.
New observational data on the internal structure constants of main-sequence stars
(Oxford Univ Press, 2017) Bulut, I.; Bulut, A.; Demircan, O.
The mean observed internal structure constant ((k) over bar (2), (obs)) values of 14 systems were revised using new data. Mean theoretical internal structure constant ((k) over bar (2, theo)) values were computed for two different metallicities (Z = 0.01 and 0.02) using Claret's models. It was found that the metallicity effect on (k) over bar (2, theo) values is too small in comparison with observational errors to estimate (k) over bar (2, obs) values. A comparison between observational and theoretical (k) over bar (2) values reveals that the (k) over bar (2, obs) values are generally smaller by up to 0.1 dex, which is, however, mostly within the observational errors of the (k) over bar (2, obs) values, i.e. the (k) over bar (2, theo) values agree well with the (k) over bar (2, obs) values within the observational errors. For three well-observed systems (PV Cas, HS Her and DR Vul), however, the (k) over bar (2, theo) values are not within the observational errors of the (k) over bar (2, obs) values but instead significantly larger. This means that the components of these systems, at least, are more centrally condensed in comparison with presently used models. Final result on the comparison between observational and theoretical (k) over bar (2) values needs further more accurate (k) over bar (2, obs) values, obtainable from more accurate space observations like the Kepler mission launched in 2009 (Borucki et al. 2010).
New times of minima of some eclipsing binary stars
(Hungarian Academy of Sciences (Konkoly Observatory), 2017) Bulut, I.; Kabaş, A.; Nehir, Ç.; Allak, S.; Neslihan, K.; Yilan, E.; Doğan, M.
[No abstract available]
Period Changes in Two Contact Binaries: V700 Cyg and PY Lyr
(Amer Inst Physics, 2016) Bulut, A.; Bulut, I.; Cicek, C.; Erdem, A.
In this paper, orbital period variations of these two contact binaries (V700 Cyg and PY Lyr) were studied. O-C diagrams of these binaries were analyzed with the least-squares method by using all available times of minima. Apparent period changes of these two contact binaries were explained in terms of light-time effect due to a third body. Masses of third bodies were found to be 0.014 +/- 0.001 M-circle dot and 0.130 +/- 0.006 M-circle dot for V700 Cyg and PY Lyr, respectively.
Period Changes of Two Contact Binaries: DF Hya and WZ And
(Amer Inst Physics, 2018) Bulut, A.; Bulut, I.
Orbital period variations of two contact binaries DF Hya and WZ And are analyzed with the least-squares method by using all available minima times. It is shown that the period variations of these systems are due mainly to the LightTime Effect (LITE) due originates from gravitational influence of a third body. New LITE elements such as, orbital periods and minimum masses of possibility third bodies are given.
The first BVR light curves and period analysis of the eclipsing binary V821 Cas
(Elsevier Science Bv, 2007) Degirmenci, O. L.; Bozkurt, Z.; Yakut, K.; Demircan, O.; Erdem, A.; Cicek, C.; Bulut, I.
The first BVR light curves of the eclipsing binary V821 Cas are used to derive the physical parameters of the system. The light curves were obtained during 2000 and 2001 observational seasons at Ege University Observatory (EUO). Period variation of the system was also investigated. For the first time apsidal motion elements of the system were obtained from the O-C curve analyses. Preliminary absolute parameters of the components were computed taking into account the results of light curves analysis. Observational and theoretical internal structure constants were estimated to be log (k) over bar (2obs) = -2.66 and log (k) over bar (2,theo) = -2.42, respectively.(c) 2006 Elsevier B.V. All rights reserved.

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