A TECHNIQUE FOR PHOTOMETRIC DETECTION AND MEASUREMENT OF UNRESOLVED BINARY-SYSTEMS

A technique is described for the detection and measurement of close bi nary systems whose images are unresolved. The method is based on analy sis of the moment-of-inertia tensor of the image, from which the produ ct of the binary flux ratio and square of the angular separation may b e determined, Intrinsic asymmetries of the point-spread function are r emoved by comparison with the image of a reference star. Multiple expo sures may be used to increase the signal-to-noise ratio without need o f image alignment. An example is given of a simulated measurement of t he dwarf carbon star system G77-61.