Photometric study and orbital period analysis of the W UMa type contact binary VZ Psc

• Published in: New astronomy Vol. 59; pp. 1 - 7
• Main Authors: Ma, S., Li, K., Li, Q.-C., Gao, H.-Y.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2018
• Subjects: Stars: binaries: contact; Stars: binaries: eclipsing; Stars: individual (VZ Psc); Stars: binaries: contact; Stars: binaries: eclipsing; Stars: individual (VZ Psc)
• ISSN: 1384-1076; 1384-1092
• DOI: 10.1016/j.newast.2017.08.004

•Four color light curves of VZ Psc are presented.•The orbital period of VZ Psc was studied by using all available times of minimum light.•VZ Psc may be a triple system. VZ Psc is a W-type contact binary system with a short period of 0.26125897 days. B, V, Rc and Ic light curves of the eclipsing binary system were obtained by using the 1.0 m reflecting telescope at Weihai Observatory of Shandong University. By collecting 136 times of minimum light, we studied the orbital period change of VZ Psc. A sinusoidal variation was discovered in the O−C diagram, and the amplitude of 0.d0023 and the period of 17.7 year were obtained. This can be caused by Applegate mechanism or light-time effect. Both the mechanisms are suited according to our investigation, but we prefer the latter that the light-time effect due to the presence of a third body results in the cyclic variation. By using the W-D program, we analyzed the four color light curves. Because of the asymmetric light curves and the possible third body, we used the spot mode of W-D program with and without L3. We found that a hot spot on the primary component with the third light leads to the best result. A very high filling factor of 94.4% ± 2.8% and orbit inclination of 53.2° were obtained.