V839 Cep—A New Quadruple Doubly Eclipsing System

Abstract

New high-precision photometric measurements of the eclipsing star V839 Cep (\(P{{ = 9.96}^{d}}\), \({{V}_{{{\text{A}} + {\text{B}}}}}{{ = 9.64}^{m}}\), \(e = 0.07\), 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 \({{\dot {\omega }}_{{{\text{obs}}}}} = 0.027^\circ \)/year, which exceeds the theoretical value under the condition of synchronism \({{\dot {\omega }}_{{{\text{theor}}}}} = 0.021^\circ \)/year. The physical parameters of the component stars of the eclipsing pair A were obtained: \({{T}_{1}} = 13{\kern 1pt} {\kern 1pt} 200 \pm 300\) K, \({{M}_{1}} = (3.7 \pm 0.15){{M}_{ \odot }}\), \({{R}_{1}} = (2.57 \pm 0.05){{R}_{ \odot }}\), \({{T}_{2}} = 11\,900 \pm 250\) K, \({{M}_{2}} = (3.2 \pm 0.15){{M}_{ \odot }}\), \({{R}_{2}} = (2.42 \pm 0.05){\kern 1pt} {{R}_{ \odot }}\), and components of the eclipsing pair B: \({{T}_{1}} = 10{\kern 1pt} {\kern 1pt} 600 \pm 200\) K, \({{M}_{1}} = (2.6 \pm 0.2){{M}_{ \odot }}\), \({{R}_{1}} = (1.97 \pm 0.05){{R}_{ \odot }}\), \({{T}_{2}} = 5540 \pm 50\) K, M₂ = \((0.88 \pm 0.05){{M}_{ \odot }}\), \({{R}_{2}} = (0.84 \pm 0.05){{R}_{ \odot }}\). The age of the system is determined to be 70 Myr with solar chemical composition. The components of star A are pulsating variable stars of the slow \(\beta \) Cephei (SBC) type.