V346 Centauri: Early-type eclipsing binary with apsidal motion and abrupt change of orbital period⋆,⋆⋆
1 Astronomical Institute of the Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 180 00 Praha 8, Czech Republic
2 Department of Astrophysics and Planetary Sciences, Villanova University, 800 East Lancaster Ave, Villanova, PA 19085, USA
3 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
4 Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
5 Institute of Physics, The Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Praha 8, Czech Republic
6 Variable Star and Exoplanet Section of the Czech Astronomical Society, Vsetínská 941/78, 757 01 Valašské Meziříčí, Czech Republic
Received: 7 April 2016
Accepted: 2 May 2016
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 6322123 to 6321843 (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.
Key words: stars: early-type / binaries: close / stars: individual: V346 Cen
Based on observations made with the ESO telescopes at the La Silla Paranal Observatory under programmes ID 083.D-0040(A), 085.C-0614(A), and 178.D-0361(B).
Tables A.2–A.6 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A129
© ESO, 2016