First study of four doubly eclipsing systems

Some of them were proved to orbit each other thanks to their eclipse-timing-variations (ETVs) of both pairs, hence they really constitute rare quadruples with two eclipsing pairs. Some of them do not, as we are still waiting for more data to detect their mutual movement.

Their light curves and period changes were analysed. All of them are detached and near-contact, but none of them contact; moreover, to our knowledge none of these stars can be considered as blend of two spatially unresolved close components on the sky. These systems are CzeV2647 (0.5723296+0.9637074 days), proved to orbit with 4.5-year periodicity; CzeV1645 (1.0944877+1.6594641 days), with a rather questionable detection of ETV; CzeV3436 (0.6836870+0.3833930 days); and, finally, OGLE SMC-ECL-1758 (0.9291925+3.7350826 days), proved to move on its 30-year orbit.