WZ Sagittae as a DQ Herculis star

Abstract

We argue that quiescent WZ Sge is a rapidly spinning magnetic rotator in which most of the matter transfered from the secondary is ejected from the system. Assuming that the observed 27.87 s oscillation period is due to the spinning white dwarf we propose that the other observed principal period of 28.96 s is a beat due to reprocessing of the rotating white dwarf beam on plasma blobs in Keplerian rotation at the outer disc rim. The weaker, transient, 29.69 s period is identified as a beat with the Keplerian period of the magnetosphere. WZ Sge evolves through a cycle of spin-up and spin-down phases. During the spin-down phase it is a DQ Her star, during the spin-up phase it should be a ER UMa star.