Absolute parameters and apsidal motion of the eccentric binary V889 Aql

We present accurate physical parameters of the eccentric binary system V889 Aql using its new spectroscopic data. According to our solutions, the system consists of two nearly identical components with primary slightly evolved. The parameters of the components are Teff1 = 10000 +/- 250 K, T-eff2 = 10500 +/- 250 K, M1 = 2.12 +/- 0.14 M-circle dot, M-2 = 2.11 +/- 0.14 M-circle dot R1 = 1.93 +/- 0.02 R-circle dot, R-2 = 1.74 +/- 0.02 R-circle dot, logL(1) = 1.52 +/- 0.05 L-circle dot, logL(2) = 1.52 +/- 0.04 L-circle dot. We verify the apsidal motion in the system and investigate the presence of a third body discussed in the literature. The internal structure constants of the components are derived for the first time. According to the O-C analysis, high rate of relativistic contribution to the apsidal motion given in the literature is confirmed and a value of the relativistic contribution of 68 per cent is obtained.