A detailed analysis of new and existing photometric , spectroscopic and spatial distribution data of the eccentric binary V731 Cep was performed .
Spectroscopic orbital elements of the system were obtained by means of cross-correlation technique .
According to the solution of radial velocities with UBVR _ { c } and I _ { c } light curves , V731 Cep consists of two main-sequence stars with masses M _ { 1 } =2.577 ( 0.098 ) M _ { \odot } , M _ { 2 } =2.017 ( 0.084 ) M _ { \odot } , radii R _ { 1 } =1.823 ( 0.030 ) R _ { \odot } , R _ { 2 } =1.717 ( 0.025 ) R _ { \odot } , and temperatures T _ { eff 1 } =10700 ( 200 ) K , T _ { eff 2 } =9265 ( 220 ) K separated from each other by a =23.27 ( 0.29 ) R _ { \odot } in an orbit with inclination of 88 ^ { \circ } .70 ( 0.03 ) .
Analysis of the O–C residuals yielded a rather long apsidal motion period of U = 10000 ( 2500 ) yr compared to the observational history of the system .
The relativistic contribution to the observed rates of apsidal motion for V731 Cep is significant ( 76 per cent ) .
The combination of the absolute dimensions and the apsidal motion properties of the system yielded consistent observed internal structure parameter ( log \bar { k } _ { 2 ,obs } = - 2.36 ) compared to the theory ( log \bar { k } _ { 2 ,theo } = - 2.32 ) .
Evolutionary investigation of the binary by two methods ( Bayesian and evolutionary tracks ) shows that the system is t = 133 ( 26 ) Myr old and has a metallicity of [ M / H ] = -0.04 ( 0.02 ) dex .
The similarities in the spatial distribution and evolutionary properties of V731 Cep with the nearby ( \rho \sim 3 ^ { \circ } .9 ) open cluster NGC 7762 suggests that V731 Cep could have been evaporated from NGC 7762 .