SuperWASP J015100.23-100524.2: A Spotted Shallow-contact Binary Below the Period Limit

SuperWASP J015100.23-100524.2 (hereafter J015100) is an eclipsing binary with an orbital period of 0.ͩ2145 that is below the short-period limit of contact binary stars. Complete light curves of J015100 in B, V, R, and I bands are presented and are analyzed with the Wilson-Devinney method. It has been discovered that J015100 is a shallow-contact binary (f = 14.6(±2.7)%) with a mass ratio of 3.128. It is a W-type contact binary where the less massive component is about 130 K hotter than the more massive one. The asymmetries of light curves are explained as one dark spot on the more massive component. The detection of J015100 as a contact binary below the period limit suggests that contact binaries below this limit are not rapidly destroyed. This shallow-contact system may be formed from a detached short-period binary similar to DV Psc (Sp. = K4/K5; P = 0.ͩ30855) via orbital shrinkage due to angular momentum loss through magnetic stellar wind.