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    BSN-III: The First Multiband Photometric Study on the Eight Total Eclipse Contact Binary Stars
    (Iop Publishing Ltd, 2025) Poro, Atila; Li, Kai; Michel, Raul; Wang, Li-Heng; Alicavus, Fahri; Alizadeh, Ghazal; Altamirano-Devora, Liliana
    This study continues our in-depth investigation of total-eclipse W Ursae Majoris-type contact binaries by analyzing eight new systems, complementing our previous work. Multiband BVRcIc photometric data were acquired through ground-based observations at an observatory in Mexico, from which new times of minima were determined. Our analysis of orbital period variations using the O - C method revealed that one system shows no long-term variation, four systems exhibit a secular decrease in their orbital periods, and two systems exhibit a secular increase, suggesting mass transfer between the components. Notably, one system displays a cyclic variation with an amplitude of 0.00865 days and a period of 10.49 yr, which we attribute to the light travel time effect induced by a tertiary companion, possibly a brown dwarf. We modeled the light curves using the PHysics Of Eclipsing BinariEs Python code. Six of the target systems required the inclusion of a cold starspot on one of the system's stars due to the asymmetry observed in the maxima of their light curves. Absolute parameters were estimated using the Gaia DR3 parallax method. Using the components' effective temperatures and masses, we classified five of the systems as W-subtype and three as A-subtype. The stellar evolution was illustrated through the mass-radius and mass-luminosity diagrams. Furthermore, we investigated the dynamical stability of two systems with extremely low mass ratios.
  • [ X ]
    Öğe
    BSN. II. The First Light Curve Study of Eight Total Eclipsing Contact Binary Stars with Shallow Fillout Factors
    (Iop Publishing Ltd, 2025) Poro, Atila; Li, Kai; Michel, Raul; Wang, Li-Heng; Alicavus, Fahri; Najera, Morgan Rhai; Santillan-Ortega, Priscila
    This study provides the first comprehensive analysis of eight total-eclipse W Ursae Majoris-type contact binary systems. Ground-based photometric multiband observations were conducted at a Mexican observatory, and new times of minima were extracted. The O-C analysis reveals that four of our target binaries exhibit a long-term increase in their orbital periods, while the others show a long-term decrease in their orbital periods. We analyzed the light curves using the PHOEBE Python code and BSN application. Among the target systems, two required the inclusion of a cold starspot on one of the components to achieve an adequate fit. The light curve analysis revealed that the target systems exhibit a shallow fillout factor. Absolute parameters were estimated using the Gaia DR3 parallax and astrophysics equations. Considering the effective temperatures and component masses, each system was classified as either the A- or W-subtype. The stellar evolution of the systems was represented through the mass-radius and mass-luminosity diagrams. Additionally, we calculated the initial masses of the companion stars and the total mass lost for each target system.
  • Küçük Resim
    Öğe
    BSN: The First Photometric Study of 10 Contact Binary Systems from the Northern and Southern Hemispheres
    (Iop Publishing Ltd, 2024) Poro, Atila; Li, Kai; Michel, Raul; Castro, Angel; Lajus, Eduardo Fernandez; Wang, Li-Heng; Coliac, Jean-Francois; Aliçavuş, Fahri
    Photometric observations were made with standard filters in four observatories for 10 contact binary systems. We analyzed the orbital period variations of the systems and found that six of them show long-term changes. The increase in the orbital period of the J07, N65, and PU Vir systems is caused by mass transfer, and the reduction in the orbital period of the J05, LO Psc, and N49 systems is caused by the combination of angular momentum loss and mass transfer. The first light-curve analysis was performed with the PHysics Of Eclipsing BinariEs Python code and Markov Chain Monte Carlo. We discussed the accuracy of photometric mass ratio estimates for contact binary systems with total and partial eclipses compared to spectroscopic results. We also compared our mass ratio findings to a recent method that estimates mass ratios from the light curve's third derivative. Then, we also discussed this new mass ratio estimate method for photometric data. The systems' positions were displayed in 18 empirical parameter relationships. According to the light-curve analysis and estimation of absolute parameters, systems BE Mus, J07, J08, N49, and N65 are A subtypes, and the others are W subtypes.