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Öğe BSN-I: the first in-depth photometric study of seven total-eclipse contact binary systems(Oxford Univ Press, 2025) Poro, A.; Li, K.; Paki, E.; Baudart, S.; Michel, R.; Wang, L.; Lajus, E. Fernandez; Aliçavuş, FahriThis is the first in-depth study of seven total-eclipse W Ursae Majoris-type contact binary systems using photometric light curves. The ground-based observations were conducted with four observatories in the Northern and Southern hemispheres. We also used the Transiting Exoplanet Survey Satellite for four target systems. We presented the analysis of orbital period variations of six systems and found that they display parabolic variations. The material transfer rates between the stars of the systems were calculated. Also, the results show that four systems have a long-term increase, while two have a long-term decrease in their orbital periods. We analysed light curves using the PHysics Of Eclipsing BinariEs python code and the Markov chain Monte Carlo algorithm to estimate different parameters of target systems and their uncertainties. Six of the target systems required the addition of a cold or hot star-spot. We estimated absolute parameters using the empirical relationship between the orbital period and the semimajor axis (P-a). According to each component's effective temperature and mass, it was recognized that the studied systems are W subtype. We examined the dynamic stability of two targets, which were low mass ratio contact binary systems. We also showed the evolution of stars in the M-R and M-L diagrams. Finally, we showed that the hotter stars in contact systems have a temperature difference of less than approximate to 400 K compared to the Gaia Data Release 3 temperature report.Öğe BSN: First Photometric Light Curve Analysis of Two W-Type Contact Binary Systems OP Boo and V0511 Cam(Springer/Plenum Publishers, 2024) Poro, A.; Tanrıver, M.; Keskin, A.; Bulut, Ahmet; Rabieefar, S.; Gharghabi, M. M.; Walter, F.This study presented the first light curve analysis of the OP Boo and V0511 Cam binary stars, which was conducted in the frame of the Binary Systems of South and North (BSN) Project. Photometric ground-based observations were conducted with standard filters at two observatories in the Czech Republic. We computed a new ephemeris for each of the systems using our extracted times of minima, TESS data, and additional literature. Linear fits for O-C diagrams of both systems were considered using the Markov Chain Monte Carlo (MCMC) method. The light curves were analyzed using the Wilson-Devinney (WD) binary code combined with the Monte Carlo (MC) simulation. The light curve solutions of both target systems required a cold starspot. The absolute parameters of the systems were calculated by using a P - M parameter relationship. The positions of the systems were also depicted on the Hertzsprung-Russell (HR), P - L, logM(tot) - logJ(0), and T - M diagrams. The hotter component in both systems is determined to be a more massive star. Therefore, it can be concluded that both systems are W-type contact binary systems.Öğe Investigation of the orbital period and mass relations for W UMa-type contact systems(Oxford Univ Press, 2022) Poro, A.; Sarabi, S.; Zamanpour, S.; Fotouhi, S.; Davoudi, F.; Khakpash, S.; Salehian, S. RanjbarNew relationships between the orbital period and some parameters of W Ursae Majoris (W UMa)-type systems are presented in this study. To investigate the relationships, we calculated the absolute parameters of a sample of 118 systems. For this purpose, we used the parallax values obtained from the Gaia Early Data Release 3 star catalogue for more precise calculations. The other required parameters, including the light-curve solutions and the orbital period, were derived from previous research. For some relationships, we added 86 systems from another study with an orbital period of less than 0.6 d to our sample, allowing us to increase the number of systems to 204. Therefore, the mass (M) values of each component along with all the other absolute parameters were recalculated for these contact systems. We used the Markov chain Monte Carlo approach in order to gain the new orbital period-mass relations (P-M) per component, and added the temperature (T) to the process to acquire the new orbital period-temperature (P-T-1) relation. We presented the orbital period behaviour in terms of log(g) by new relations for each component. We have also obtained a model between the orbital period, the mass of the primary component, and temperature (P-M-1-T-1) using the artificial neural network method. Additionally, we present a model for the relationship between the orbital period and the mass ratio (P-q) by fitting a multilayer perceptron regression model to a sample of the data collected from the literature.Öğe The first light curve solutions and period changes of EW Psc and HN Psc(Elsevier, 2020) Davoudi, F.; Poro, A.; Alicavus, F.; Rahimi, J.; Lashgari, E.; Ghanbarzadehchaleshtori, M.; Boudesh, A.The first light curve solutions of the stars EW and HN in the Pisces constellation are presented. Photometry, and its' periodic changes are calculated and discussed. The analysis of the O-C diagram is done by the MCMC approach in the OCFit code and a new ephemeris is provided for the two binary systems. The results show that EW Psc is a near contact eclipsing binary system with a photometric mass ratio q = 0.587, and the fillout factor is -0.034 and -0.018 for the primary and secondary components, respectively. The solution results also show that the system HN Psc is a weak-contact W UMa eclipsing binary with a photometric mass ratio q = 0.853, and with a fillout factor of 5.6%. The light curves solutions required a cold spot to account for the O'Connell effect.Öğe The First Light Curve Solutions and Period Study of BQ Ari(Springer, 2021) Poro, A.; Davoudi, F.; Kahraman Aliçavuş, Filiz; Khakpash, S.; Esmer, E. M.; Baştürk, O.The first analysis of the photometric observation in BVR filters of a W UMa type binary system BQ Ari was performed. Light curve analysis was performed using Wilson-Devinney (W-D) code combined with a Monte Carlo (MC) simulation to determine its photometric and geometric elements and their uncertainties. These results show that BQ Ari is a contact binary system with a photometric mass ratio q = 0.548 +/- 0.019, a fillout factor f = 24 +/- 0.8%, and an orbital inclination of i = 85.09 +/- 0.45. We used the parallax from Gaia EDR3 for calculating the absolute parameters of the binary system. This study suggested a new linear ephemeris for BQ Ari, combining our new mid-eclipse times and the previous observations, which we analyzed using the Monte Carlo Markov Chain (MCMC) method. We present the first analysis of the system's orbital period behavior by analyzing the O - C diagram using the Genetic Algorithm (GA) and the MCMC approaches in OCFit code. We attempted to explain the analysis of the residuals of linear fit in the O - C diagram with two approaches; "LiTE + Quadratic" and "Magnetic activity + Quadratic." Although we consider the magnetic activity to be probable, the system should be studied further in order to reveal the nature of orbital period variations.
