长蛇座DF的光电测光和研究

PHOTOELECTRIC PHOTOMETRY AND STUDY OF DF HYDRA

本文给出了长蛇座DF的BV双色光电光变曲线.发现该双星的轨道周期是变化的,并给出了计算它的光变极小时刻的新的历元公式.用Wilson和Devinney综合光变曲线法程序分析新的观测资料,求得了DF Hya的测光解.用不同方法求得了该双星相一致的基本参量.研究表明DF Hya是一颗未演化的零龄主序相接双星.

The photoelectric photometric observations of DF Hydra in B and V were made in 1985. Two primary minimum times and two secondary minimum times of light were determined from our observations. The period of DF Hya was found to be changing and the new light ephemeris found by least square method is the following: Min. I=JD he1.2445021.5009+0.33060443E+7.5*10^(-11)E^2. An extensive search for a reliable mass ratio q was carried out by using the Wilson and Devinney method. The photometric solutions found from the two light curves in B and V are listed in Table 6. The absolute dimensions of DF Hya found by Liu (1987, 1989)'s method and Dworak (1975)'s method, respectively, are listed in Table 7. According to Liu (1987)'s method, it is possible that DF Hya is an unevolved contact binary system.