IP Lyn:A Totally Eclipsing Contact Binary with an Extremely Low Mass Ratio  

作　　者：Zi-Xuan Yin Zi-Bin Meng Pei-Ru Wu Xu-Dong Zhang Yun-Xia Yu Ke Hu Fu-Yuan Xiang 

机构地区：[1]Key Laboratory of Star and Interstellar Medium,Xiangtan University,Xiangtan 411105,China [2]School of Physics and Electronic Science,Guizhou Normal University,Guiyang 550025,China [3]Department of Physics,Xiangtan University,Xiangtan 411105,China

出　　处：《Research in Astronomy and Astrophysics》2023年第8期206-219,共14页天文和天体物理学研究（英文版）

基　　金：supported by the Joint Research Funds in Astronomy under a cooperative agreement between the National Natural Science Foundation of China(NSFC)and the Chinese Academy of Sciences(Nos.U1931115 and U2031114);Scientific Research Fund of Hunan Provincial Education Department grant No.22A0099;the support of the staff of the Xinglong 85 cm telescope;partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。

摘　　要：We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations suggest that it is a shallow contact binary with an extremely low mass ratio of 0.055.The weak asymmetry observed in our multiple band light curves can be interpreted as a result of an active cool spot on the primary.The absolute physical parameters were determined with the Gaia-distance-based method and checked by an empirical relation.Combining the eclipse timings collected from the literature and those derived from our and variable surveys'observations,we find that IP Lyn has been undergoing a secular orbital period increase for the past two decades,implying a mass transfer from the less massive secondary to the primary.By comparing the current parameters with the critical instability ones,we infer that IP Lyn is currently stable in spite of its relatively low mass ratio and orbital angular momentum.Finally,from a catalog of 117 extremely low mass ratio contact binaries,we find that their orbital angular momenta are significantly lower than those of the contact binaries with a relatively high mass ratio,suggesting they should be at the late evolutionary stage of a contact binary.

关 键 词：(stars")binaries(including multiple) close-(stars:)binaries eclipsing-stars evolution-stars individual(IP Lyn) 

分 类 号：P153[天文地球—天文学]