An oblique rotator model for DQ Herculis

It is suggested that the old nova DQ Herculis and the known pulsing X-ray sources belong to a common class of magnetic, accreting, compact components in close semi-detached binary systems. The 71-s periodicity observed in the white dwarf component of DQ Herculis is interpreted as due to accretion hot spots on an oblique magnetic rotator. The model requires that the magnetic field is ≳ 10 6 G and that the spots should radiate predominantly in the far UV/soft X-ray region. The model predicts a phase shift in the periodicity of | ϕ | = 360° through the eclipse of the white dwarf. The sign of the observed 360° phase change is inconsistent with the sign expected from this model.