First TESS-based photometric analysis of the solar-like contact binaries EI Sge and U Ret
Advances in Space Research, cilt.78, sa.8, ss.8595-8605, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 78 Sayı: 8
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.asr.2026.08.034
- Dergi Adı: Advances in Space Research
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Compendex, INSPEC, MEDLINE, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Sayfa Sayıları: ss.8595-8605
- Anahtar Kelimeler: Binaries, Contact - stars, Eclipsing - binaries, Fundamental parameters - stars, Individuals (EI Sge and U Ret)
- Hakkari Üniversitesi Adresli: Evet
Özet
Using light curves (LCs) obtained from the Transiting Exoplanet Survey Satellite (TESS), we have performed for the first time a photometric analysis of two solar-like eclipsing binaries (EBs), EI Sge and U Ret. The term ”solar-like” adopted in this study refers to their derived physical properties (effective temperatures, masses and luminosities close to solar values) rather than to spectroscopically confirmed spectral classifications. The LCs were modeled with the Wilson–Devinney (WD) method, and we found that both systems exhibit a contact binary (CB) configuration, with fill-out factors of about 20% and 26%, respectively. The mass ratios ((Formula presented)) were derived as 0.594 for EI Sge and 0.566 for U Ret. The estimated physical parameters for EI Sge are (Formula presented), and (Formula presented). For U Ret, we obtained (Formula presented), and (Formula presented). In both systems, a cool spot was modeled on the secondary object, suggesting magnetic activity. Furthermore, from an (Formula presented) analysis combining available minima times (MTs) with new ones derived from the TESS data, we identified continuous orbital period (OP) decreases at rates of (Formula presented) days year−1 for EI Sge and (Formula presented) days year−1 for U Ret. Under the assumption of conservative material (energy) transfer, the corresponding material (energy) transfer rates were calculated as (Formula presented) year−1 and (Formula presented) year−1, respectively. The periodic variation could be attributed to the light-time effect (LITE) of a third object or a magnetic activity mechanism. To test the accuracy of the parameters obtained for both EI Sge and U Ret, and to better understand the nature of these systems, they were plotted on logMtot–logJ and logTeff–logL diagrams alongside systems with similar physical properties. In general, our findings indicate that EI Sge and U Ret are solar-like contact binaries (CBs) and provide important observational reference points for understanding the long-term evolutionary behavior of such systems.