70
Intermediate Polars: Fast-spinning systems
Some Intermediate Polars have very short spin periods, for example DQ Her: 71 sec, AE Aqr: 33 sec
In this case the magnetic field is thought to be small, so that the hollowed-out part of the disk is also small and the Keplarian velocities in the field coupling region large
AE Aqr is a special case: the white dwarf spin period is decreasing rapidly, and it can be calculated that almost all of the luminosity of the system arises as a result of the spin-down energy
Spinning white dwarf kicks the gas from the stream out of the system – propellor
Much of the optical and radio emission from the system arises in colliding shocks in the ejecta
Wynn, King & Horne (1997)