New high-precision CCD photometric light curves of two contact binary stars, TYC 1337-1137-1 and TYC 3836-0854- 1, are displayed and analyzed by using the Wilson-Devinney(W-D) program. The light curve solutions show that both of them are low-mass ratio, deep overcontact binary systems with a mass ratio of q = 0.1716. +/- 0.0010 and a high fillout factor of f. = 76.0. +/- 2.9% for TYC 1337-1137-1, and q = 0.1900. +/- 0.0032 and f = 79.4. +/- 7.9% for TYC 3836-0854-1, respectively. These results indicate that they are near the end evolutionary stage of contact binaries. The absolute parameters were calculated by using the new method of mass-radius relationship (0.238 +/- 0.009 M-circle dot and 1.386 +/- 0.050 M-circle dot for TYC 1337-1137-1, 0.228 +/- 0.014 M-circle dot and 1.20 +/- 0.07 M-circle dot for TYC 3836-0854-1, respectively). The preliminary orbital period analysis suggests that long-term period increases exist for both of them, which may be interpreted in two possible ways. A first possibility is mass transfer conservation from the less massive component to the more massive one leading to an orbital period increase. In this case, when their orbital angular momentum is less than three times the total spin angular momentum, they may evolve into a rapidly rotating single star. A second possibility is that the parabolic variation in the (O- C) diagram is only a part of a long-period cyclic change caused by a potential third body. In future, more high-precision observations of these two binaries are needed to confirm the form of orbital period changes.
项目资助者:
National Natural Science Foundation of China(11403095, 11325315, 11611530685)
; Yunnan Natural Science Foundation(2014FB187)
; National Development and Reform Commission
1.Yunnan Observatories, Chinese Academy of Sciences (CAS), P.O. Box 110, 650216 Kunming, China 2.Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, 650216 Kunming, China 3.Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012, China 4.University of the Chinese Academy of Sciences, Yuquan Road 19#, Shijingshan Block, 100049 Beijing, China 5.National Astronomical Research Institute of Thailand, 191 Siripanich Bldg., Chiang Mai 50200, Thailand 6.Sternberg Astronomical Institute, Moscow State University, Universitetskij prospect 13, Moscow 119992, Russia
Recommended Citation:
Liao WP,Qian SB,Soonthornthum, B.,et al. TYC 1337-1137-1 and TYC 3836-0854-1: Two Low-mass Ratio, Deep Overcontact Systems Near the End Evolutionary Stage of Contact Binaries[J]. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC,2017,129(982).
