Close binary system GO Cyg

• Published in: New astronomy 2012-04, Vol.17 (3), p.296-302
• Main Authors: Ulaş, B., Kalomeni, B., Keskin, V., Köse, O., Yakut, K.
• Format: Article
• Language: English
• Subjects: Stars: binaries: close; Stars: binaries: eclipsing; Stars: binaries: general; Stars: fundamental parameters; Stars: low-mass
• ISSN: 1384-1076; 1384-1092
• DOI: 10.1016/j.newast.2011.09.002

► Long term photometric variation of the close binary system GO Cyg is investigated. ► The orbital and physical parameters of the system are determined. ► The results show that the system is the most massive system among the known near contact binaries. In this study, we present long term photometric variations of the close binary system GO Cyg. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical parameters of the system are M 1 = 3.0 ± 0.2 M ⊙, M 2 = 1.3 ± 0.1 M ⊙, R 1 = 2.50 ± 0.12 R ⊙, R 2 = 1.75 ± 0.09 R ⊙, L 1 = 64 ± 9 L ⊙, L 2 = 4.9 ± 0.7 L ⊙, and a = 5.5 ± 0.3 R ⊙. Our results show that GO Cyg is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of 92.3 ± 0.5 yr due to a third body whose mass is less than 2.3 M ⊙. Finally a period variation rate of −1.4 × 10 −9 d/yr has been determined using all available light curves.