A photometric-spectroscopic study of the infrared-excess eclipsing binary V2364 Cyg

The eclipsing binary V2364 Cyg is an A7V-type contact binary with a period of 0.5921 d. We present six spectra from LAMOST and BVRc light curves (LCs), which are simultaneously analyzed to obtain the absolute physical parameters. The first light maxima are brighter than the second ones by up to 0.m038 , 0.m036 and 0.m024 for BVRc bands, respectively. These distorted LCs are modeled by a cool spot on the less massive component. Its mass ratio and over-contact degree are q = 0.319(±0.004) and f = 28.4%(±1.0)% respectively. From the mass-luminosity diagram, the primary component is a normal main-sequence star, while the secondary one is a subgiant star. From the (O - C) curve, the orbital period secularly decreases at a rate dP/dt = -1.62(±0.03)×10−7d yr−1, which is mainly attributed to mass loss via stellar wind from the binary system. This may result in the observed infrared excess in the W4 band.