V839 Cep – a new quadruple doubly eclipsing system

New high-precision photometric measurements of the eclipsing star V839 Cep (P = 9.96^d, V_A+B = 9.64^m, e = 0.07, B6 V + B7 V), which is the “A” component of the visual double star J21035+5925AB, have established that component “B” is also an eclipsing variable (P = 4.075^d, B9 V + G8 V). For component “A”, the apsidal rotation rate was measured to be ${\dot{\mathrm{\omega }}}_{\mathrm{obs}} = 0.027° /\mathrm{year}$, which exceeds the theoretical value under the condition of synchronism ${\dot{\mathrm{\omega }}}_{\mathrm{theor}} = 0.021° /\mathrm{year}$. The physical parameters of the component stars of the eclipsing pair “A” were obtained: T₁ = 13 200 ± 300 K, M₁ = (3.7 ± 0.15) M_⊙, R₁ = (2.57 ± 0.05) R_⊙, T₂ = 11 900 ± 250 K, M₂ = (3.2 ± 0.15) M_⊙, R₂ = (2.42 ± 0.05) R_⊙ and components of the eclipsing pair “B”:  T₁ = 10 600 ± 200 K, M₁ = (2.6 ± 0.2) M_⊙, R₁ = (1.97 ± 0.05) R_⊙, T₂ = 5540 ± 50 K, M₂ = (0.88 ± 0.05) M_⊙, R₂ = (0.84 ± 0.05) R_⊙. The age of the system is determined to be 70 million years with solar chemical composition. The components of star “A” are pulsating variable stars of the slow β Cephei (SBC) type.