arXiv subjects

Razieh Aliakbari

Publications and source records attributed to Razieh Aliakbari.

4 recordsLinked to original sources

arXiv2026

BSN: Light Curve Modeling and Orbital Period Analysis of the Contact Binaries OV Leo and V339 Leo

We present a combined photometric and orbital period analysis of the contact binary systems OV Leo and V339 Leo using ground-based observations together with TESS photometry. The light curves were modeled with the BSN software through a Markov Chain Monte Carlo approach, providing physical estimates of the system parameters and their uncertainties. OV Leo is analyzed photometrically for the first time, while V339 Leo is reexamined using new observations and an updated modeling methodology. The light curve analysis show that both targets are W-subtype contact binaries in shallow-contact configurations. The O'Connell effect detected in V339 Leo is reproduced with a cool starspot model, whereas no spot is required for OV Leo. Three-dimensional geometric models further indicate that OV Leo undergoes total eclipses, while V339 Leo exhibits partial eclipses. Orbital period analysis based on eclipse timing extractions reveals opposite long-term period variations in the two systems, suggesting ongoing mass transfer under the assumption of conservative mass transfer. The absolute parameters were derived using the Gaia parallaxes, the photometric light curve solution, and standard astrophysical equations.

astro-ph.SR↗

arXiv2025

Four Total Eclipsing Contact Binary Systems: The First Photometric Light Curve Solutions Employing TESS and Gaia Surveys

We presented the first photometric light curve solutions of four W Ursae Majoris (W UMa)-type contact binary systems. This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite (TESS) and Gaia Data Release 3 (DR3). We used the PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the Markov Chain Monte Carlo (MCMC) method for these light curve solutions. Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis. Based on the estimated mass ratios for these total eclipse systems, three of them are categorized as low mass ratio contact binary stars. The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semi-major axis ($P-a$) empirical relationship. We defined that TIC 318015356 and TIC 55522736 systems are A-subtypes, while TIC 249064185 and TIC 397984843 are W-subtypes, depending on each component's effective temperature and mass. We estimated the initial masses of the stars, the mass lost by the binary system, and the systems' ages. We displayed star positions in the mass-radius, mass-luminosity, and total mass-orbital angular momentum diagrams. In addition, our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.

astro-ph.SR↗

arXiv2025

The First In-depth Photometric Study of the Four Delta Scuti Stars Using TESS Data

The first in-depth photometric study of four Delta Scuti stars was performed. We used time series data from the Transiting Exoplanet Survey Satellite (TESS) that is available in different sectors. According to the extracted maxima from TESS space-based observations, we calculated an ephemeris for each star. We estimated the physical parameters of the target stars based on the Gaia Data Release 3 (DR3) parallax method. The results obtained for the surface gravity of the stars are consistent with the reports of the TESS Input Catalog and Gaia DR3. We estimated the pulsating constant based on the physical parameters and period of the stars. Therefore, we found that the stars 2MASS 15515693-7759002 and 2MASS 07513202+0526526 belong to the fundamental, while 2MASS 00044615+4936439 and 2MASS 10215638-3326137 relate to the first overtone. The Fourier analysis using the Period04 program was done for each star. As we showed in the Hertzsprung-Russell (H-R) diagram, the stars are located in the instability strip of the Delta Scuti stars region. Four target stars were found to be of the low-amplitude Delta Scuti star type.

astro-ph.SR↗

arXiv2024

Estimating the Absolute Parameters of W UMa-type Binary Stars Using Gaia DR3 Parallax

The accuracy of absolute parameters' estimation in contact binary systems is important for investigating their evolution and solving some challenges. The Gaia DR3 parallax is one of the methods used for estimating the absolute parameters, in cases where photometric data is the only one that is available. The use of this method includes advantages and limitations that we have described and examined in this study. We selected 48 contact binary systems whose mass ratios were mostly obtained by spectroscopic data, in addition to a number of photometric studies. The target systems were suitable for A_V and the Re-normalised Unit Weight Error (RUWE), and their absolute parameters were calculated based on Gaia DR3 parallax, observational information, orbital period, and light cure solution from the literature and catalogs. The outcomes of OO Aql differed significantly from those reported in the literature. Upon analyzing the system's light curve with TESS data, we concluded that the stars' temperatures were the reason for this difference, and utilizing Gaia DR3 parallax provided reasonable results. We displayed the target systems on the Hertzsprung-Russell (HR), q-L_ratio, P-M_V, and logM_tot-logJ_0 diagrams, and the systems are in good agreement with the theoretical fits. We showed that the estimation of absolute parameters with this method might be acceptable if Delta a(R_Sun) is less than about 0.1(R_Sun). There are open questions regarding the existence of l_3 in the light curve analysis and its effect on the estimation of absolute parameters with this method.

astro-ph.SR↗