The Photometric Research Of EB-type Eclipsing Binary In Open Cluster NGC 869

In open clusters, eclipsing binaries are crucial to the research of stellar structure and evolution. By means of photometric solutions and observations of radial velocity, the mass, radii of the both stars in a binary system can be obtained. As members of open cluster, from other methods we can clearly know its distance, age, and metallicit y of these stars. These make that eclipsing binaries in open clusters is a perfect object for the study of binary star structure and evolution theory. We perform a time-series B-band and V-band CCD photometry for an EB-type eclipsing binary NSVS 1908107 which belongs to the young open cluster NGC 869. With the Wilson-Devinny method,the photometric solution of NSVS 1908107 was obtained. It suggests that the system is a semidetached binary and the secondary component fills its Roche lobe. The mass ratio of both stars was calculated to be 0.059 ± 0.001. Using the physical properties of open cluster NGC 869, the masses, radii, and luminosities of NSVS 1908107 are determined to be M₁ = 10.34± 2.29 M_⊙, R₁ = 4.65± 0.34 R_⊙, L₁ = 8076± 371 L_⊙ and M₂ = 0.61± 0.13M_⊙, R₂ = 2.40± 0.17 R_⊙, L₂ = 1054± 48 L_⊙. From the final results we conclude that the secondary star may be a giant or sub-giant star which its outer envelope is being stripped.