Yazar "Bulut, A." seçeneğine göre listele
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Öğe A Combined TESS and Ground-based Study of Transit Timing Variations in HAT-P-16, TOI-1516 and TOI-2046 Systems(Iop Publishing Ltd, 2025) Sonbas, E.; Kaplan, K.; Tanriver, M.; Keskin, A.; Dhuga, K.; Bulut, A.; Gogus, E.We present new results for the hot Jupiters HAT-P-16b, TOI-1516b, and TOI-2046b, based on photometric observations collected using both space- and ground-based facilities. Ground-based data were collected in the 2020-2024 time span with the 0.6 m telescope (ADYU60) located at the Adiyaman University Application and Research Center (Adiyaman, T & uuml;rkiye) and the 1.0 m telescope at the T & uuml;rkiye National Observatory (TUG, T & uuml;rkiye). Through a combination of fits to our ground-based data, the midtransit times data from TESS, and additional data taken from the literature, we present an updated linear ephemeris for each system. Transit timing variations (TTVs) were analyzed using linear, orbital decay, and apsidal precession models. The resulting BIC(Delta BIC) values indicate that the orbital decay model is statistically favored for HAT-P-16b and TOI-1516b, while the constant period model is preferred for TOI-2046b. False alarm probabilities (FAPs) were computed to assess the significance of any periodic signals. TOI-1516b displays a strong TTV signal with a FAP (of 0.0001) well below the 0.01 threshold, suggesting a likely dynamical origin that warrants further investigation. The higher FAP value (0.0055) for HAT-P-16b suggests that the case of a possible presence of an additional body in the system is less convincing. In contrast, the much higher FAP value (0.0196) for TOI-2046b implies that there are no statistically significant TTVs.Öğe 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.Öğe 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.Öğe 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.Öğe 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.Öğe 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.Öğe 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.Öğe 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 orbitÖğe 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.Öğe 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).Öğe 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.Öğe 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.Öğe The Light Curve Analysis of The Highly Eccentric Eclipsing Binary KIC 10296163(Amer Inst Physics, 2019) Cicek, C.; Bulut, A.; Bulut, IIn this study, the analysis of the Kepler light curve of the eclipsing binary KIC 10296163 (Gaia DR2 2085670964017513856, R.A.(2000) = 19(h)564(m)40(s).07, DEC2000 = +47(0) 21'21 ''.97, m(R) = 13.43 mag) is presented. The light curve of the system shows a secondary minimum from a shifted phase 0.5 which indicates the ellipticity of the orbit. By using the PHOEBE program we analysed the light curve to achieve the orbital parameters of the system. The results of our analysis indicates a detached system where the orbit is highly eccentric (e = 0.357 +/- 0.003). Therefore, KIC 11858541 is a suitable candidate for apsidal motion studies.Öğe Third Body Effects in The Period Changes of Two Algol Binaries: V342 Aql and TW Lac(Amer Inst Physics, 2017) Cicek, C.; Bulut, I.; Bulut, A.The O - C diagrams of two Algol-type eclipsing binaries V342 Aql and TW Lac have been analyzed with the least-squares method by using all available minima times. The period changes in their O - C diagrams have been discussed with respect to the Light-Time Effect (LITE) that originates from gravitational influence of a third body. New LITE elements, orbital periods and possible minimum masses of third bodies are given.
