* Astronomy

Title: CCD Photometric Study of the Contact Binary TX Cnc in the Young Open Cluster NGC 2632
Authors: Liu Liang, Qian Shengbang, BOONRUCKSAR Soonthornthum, Zhu Liying, He Jiajia, J.-Z. Yuan

TX Cnc is a member of the young open cluster NGC 2632. In the present paper, four CCD epochs of light minimum and a complete V light curve of TX Cnc are presented. A period investigation based on all available photoelectric or CCD data showed that it is found to be superimposed on a long-term increase (dP/dt=+3.97 x {10^{-8}}\,days/year), and a weak evidence suggests that it includes a small-amplitude period oscillation (A_3=0.^{d}0028; T_3=26.6\,years). The light curves in the V band obtained in 2004 were analysed with the 2003 version of the W-D code. It was shown that TX Cnc is an overcontact binary system with a degree of contact factor f=24.8%(±0.9%). The absolute parameters of the system were calculated: M_1=1.319±0.007 solar masses, M_2=0.600±0.01 solar masses; R_1=1.28±0.19 solar radii, R_2=0.91±0.13 solar radii. TX Cnc may be on the TRO-controlled stage of the evolutionary scheme proposed by Qian (2001a, b; 2003a), and may contains an invisible tertiary component (m_3 ~0.097 solar masses). If this is true, the tertiary component has played an important role in the formation and evolution of TX Cnc by removing angular momentum from the central system(Pribulla & Rucinski, 2006). In this way the contact binary configuration can be formed in the short life time of a young open cluster via AML.

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