双星与变星研究组知识库

HT Vir is a well-known quadruple system with three components visible in the spectra. However, the cyclic variation of the O - C diagram has not been presented until now. To search for a variation in the O - C diagram of HT Vir, we monitored it from 2007 March to 2009 February, and as a result, 7 times of light minimum were obtained. Also, 3 times of light minimum were determined by us with photoelectric data obtained at Mt. Suhora observatory by using three channel photometers attached on the 60-cm Cassegrain telescope (Zola et al. 2005). Based on 56 times of light minimum, we report the discovery of a cyclic variation in the orbital period of HT Vir. It was found that the orbital period of the binary shows a 30.5 yr cyclic change with a semiamplitude of 0.0066 d. The period variation may be caused by a disturbance of component A to the contact system orbit. More times of light minimum with high precision are needed to check the nature of the O - C plot in the future.