Neglected reverse Algol system: WZ Hor

Abstract

This paper presents the first analysis of spectroscopic and photometric observations of the eclipsing binary star WZ Hor. Observations of the system were made at the Mt. John University Observatory in 2007. Since the light contribution of the secondary component was merely 2–3% of the total light of the system in the optical wavelengths, the radial velocity of the primary component could only be determined using the cross-correlation method. A single-lined spectroscopic orbital solution of WZ Hor was obtained, and the BVRI light curves of the system and radial velocity curve of the primary component were analysed simultaneously using the Wilson–Devinney method. The results describe WZ Hor as a reverse Algol-like binary star with a detached configuration. The following absolute parameters of the components were also derived: M 1 = 1.51 ± 0.03 M ⊙, M 2 = 0.66 ± 0.01 M ⊙, R 1 = 1.62 ± 0.02 R ⊙, R 2 = 0.66 ± 0.01 R ⊙, L 1 = 4.93 ± 0.64 L ⊙ and L 2 = 0.09 ± 0.02 L ⊙. The distance to WZ Hor was calculated as 95 ± 8 pc using distance modulus with correction for interstellar extinction, in agreement with the HIPPARCOS value.