Optical and X-ray observations of AO PISCIUM and the origin of the spin pulse in intermediate polars.

Abstract

Results are presented of three nights of time-resolved spectroscopic observations and of four Exosat X-ray observations of the AO Psc polar binary. It is found that the AO Psc has a magnetic field much weaker than that of the AM Her star and that it possesses an accretion disc extending inward to about 8 white-dwarf radii and outward to fill the Roche lobe (about 5 x 10 to the 10th cm). The findings are compared with those from other intermediate polars, and the implications of the findings for the class of intermediate polar binaries as a whole are discussed.