V839 Cep – a new quadruple doubly eclipsing system

New high-precision photometric measurements of the eclipsing star V839 Cep (P = 9.96d, VA+B = 9.64m, 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 = 4.075d, B9 V + G8 V). For component “A”, the apsidal rotation rate was measured to be ω˙obs=0.027°/year, which exceeds the theoretical value under the condition of synchronism ω˙theor=0.021°/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.