Photometric and spectroscopic studies of six W UMa-type eclipsing binaries

ABSTRACT We performed new photometric and spectroscopic studies on six W UMa-type eclipsing binaries (V342 UMa, LX Leo, V1062 Her, V801 And, 1SWASP J165649.13+402738.4, and V1067 Her). From orbital period analysis, V342 UMa and LX Leo show continuous period decrease with a rate of −2.11($\pm$0.06) $\times$ 10$^{-7}$ and −6.02$(\pm 0.13)$ × 10$^{-8}$ d yr$^{-1}$, respectively. Another four targets show cyclic variation, which could be caused by the light-travel-time effect via the third body. In addition, using the spectral subtraction technique, we analysed the low-resolution Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra of the five objects and detected the ${\rm{H}} \, {\alpha }$ emission line, which implies chromospheric activity. In addition, the light curves of these systems show an obvious O’Connell effect. Using the Wilson–Devinney code, we also obtained their photometric solutions. It is suggested that V1067 Her is a medium contact binary; others are shallow contact eclipsing binary systems. Based on photometric solutions, Gaia and LAMOST data, we calculated the absolute parameters of these targets. We also discussed their evolutionary status and found that these targets are stable for the moment. The third body may play an important role in the formation and evolution of these short-period eclipsing binaries.