Abstract
New physical elements of the early B-type eclipsing binary V346 Cen are derived using the HARPS spectra downloaded from the ESO archive and also numerous photometric observations from various sources. A model of the observed times of primary and secondary minima that fits them best is a combination of the apsidal motion and an abrupt decrease in the orbital period from 6(d).322123 to 6(d).321843 (shortening by 24 s), which occurred somewhere around JD 2 439 000.
Assumption of a secularly decreasing orbital period provides a significantly worse fit. Local times of minima and the final solution of the light curve were obtained with the program PHOEBE.
Radial velocities of both binary components, free of line blending, were derived via 2D cross-correlation with a program built on the principles of the program TODCOR. The oxygen lines in the secondary spectra are weaker than those in the model spectra of solar chemical composition.
Using the component spectra disentangled with the program KOREL,we find that both components rotate considerably faster than would correspond to the synchronization at periastron. The apside rotation known from earlier studies is confirmed and compared to the theoretical value.