The eclipse light curves of UZ for

Abstract

CCD high-speed photometric observations of the eclipse light curves of the AM Herculis binary UZ For (EXO 033319 - 2554.2) are presented. We also present circular polarization observations at lower time resolution, covering the whole binary cycle. The eclipse light curves are clearly resolved into two components which can be identified with the white dwarf photosphere, and the accretion spot on its surface. This provides a particularly direct confirmation of the standard model of AM Herculis systems. By modelling the eclipse light curve we are able to set constraints on the geometrical parameters of the binary system, and the location of the accretion spot. The duration of the ingress and egress of the white dwarf eclipse constrains the radius and hence mass of the white dwarf. We find that the white dwarf mass is between 0.61 and 0.79 M⊙. The accretion spot is found to have a radius of about 0.12 times the radius of the white dwarf.