The photometric reflection effect in close binaries

A method for evaluating the photometric consequences of the reflection effect in close binaries is described. There is no restriction on the extent of the penumbra and the conversion to monochromatic radiation avoids the ambiguity of the approach based on application of a luminous efficiency factor. The reflected radiation is taken to have a phase law of the form (1–u _r+u _rcos) where represents the angle between the local normal and the observer's line of sight.An estimate of the accuracy of the method is made; it is found that it is suitable for the reduction of light curves of high precision for all systems except those where the components are in contact or almost so.