ON THE STATISTICS OF AM HERCULIS BINARIES

The magnetic field and orbital period distributions of AM Herculis bin aries are investigated. Our study shows that (i) there is a significan t lack of very-high-field magnetic white dwarfs in binaries when compa red with isolated white dwarfs, and (ii) the difference between the pe riod distributions of AM Herculis binaries and other cataclysmic varia ble subclasses is statistically significant. These results imply that the evolution and the birth of AM Herculis binaries are different from those of other cataclysmic variables.