Intermediate polar

In intermediate polar systems, the same general scenario applies except that the inner disk is disrupted by the magnetic field of the white dwarf.

Only two of them are brighter than 15th magnitude at minimum: the prototype DQ Herculis, and the unusual slow nova, GK Persei.

The x-rays are generated by high velocity particles from the accretion stream forming a shock as they fall onto the surface of the white dwarf star.

As particles decelerate and cool before hitting the white dwarf surface, bremsstrahlung x-rays are produced and may subsequently be absorbed by gas surrounding the shock region.

The physical cause of optical spin-period oscillations is usually attributed to the changing viewing aspect of the accretion curtain as it converges near the white dwarf.

All three periodic signals may be measured by taking a fourier transform of the light curve and producing a power spectrum.

Diagram of an intermediate polar. Matter flows from the companion star into an accretion disk around the white dwarf , but is disrupted by the white dwarf's magnetic field.