BSN-VI: Multiband Light Curve Modeling of Four W UMa-Type Contact Binaries I. Revisiting Energy Transfer Mechanisms and Luminosity Behavior
We presented the first high-precision, detailed photometric analysis of four W Ursae Majoris (W UMa)-type contact binaries, Linear 10772300, Linear 11150338, Linear 20372537 and DM Cir. In addition to ground-based multiband photometric observations, data from the Transiting Exoplanet Survey Satellite (TESS) were employed for the analysis of the DM Cir system. New ephemeris and linear fit to the O-C diagrams were derived using extracted times of minima and additional literature. The light curve modeling was performed using the PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the BSN application, employing a Markov Chain Monte Carlo approach. In each systems, the two stellar components exhibited minimal temperature differences ($ΔT<150$ K), confirming efficient energy exchange within their common convective envelopes. Absolute parameters were estimated using the Gaia Data Release 3 (Gaia DR3) parallax and astrophysical equations. Based on effective temperatures and component masses, two systems were classified as W-subtype systems, while others belonged to the A-subtype. We computed the initial masses of the primary ($M_{1i}$) and secondary ($M_{2i}$) components for four target systems using a method based on the observational properties of overluminous secondary components. We found initial primary masses in the range 0.6-1.0$M_\odot$ and initial secondary masses in the range 0.9-1.7$M_\odot$ with mass loss $<1.0M_{\odot}$. We investigated the relative energy transfer rates ($U_{1}$ and $U_{2}$) and nuclear luminosities ($L_{10}$ and $L_{20}$) based on the physical parameters of 411 W UMa-type contact binaries, including the four systems analyzed in this study, through wide range of mass ratios. The results for all systems provided a comprehensive view of energy transfer behavior throughout different evolutionary stages of contact binaries.