AE Aquarii represents a new subclass of Cataclysmic Variables

TL;DR

AE Aquarii is a unique nova-like star with a magnetized white dwarf in an ejector state, representing a new subclass of Cataclysmic Variables, bridging the gap between Polars and recycled pulsars.

Contribution

This study identifies AE Aquarii as a new subclass of Cataclysmic Variables with a white dwarf in the ejector state, distinct from known subclasses.

Findings

White dwarf in AE Aqr is in the ejector state.

Magnetic dipole moment is approximately 1.5 x 10^{34} G cm^3.

White dwarf resembles a recycled pulsar.

Abstract

We analyze properties of the unique nova-like star AE Aquarii identified with a close binary system containing a red dwarf and a very fast rotating magnetized white dwarf. It cannot be assigned to any of the three commonly adopted sub-classes of Cataclysmic Variables: Polars, Intermediate Polars, and Accreting non-magnetized White Dwarfs. Our study has shown that the white dwarf in AE Aqr is in the ejector state and its dipole magnetic moment is $\mu ~ 1.5 \times 10^{34} G cm^3$. It switched into this state due to intensive mass exchange between the system components during a previous epoch. A high rate of disk accretion onto the white dwarf surface resulted in temporary screening of its magnetic field and spin-up of the white dwarf to its present spin period. Transition of the white dwarf to the ejector state had occurred at a final stage of the spin-up epoch as its magnetic field emerged from the accreted plasma due to diffusion. In the frame of this scenario AE Aqr represents a missing link in the chain of Polars evolution and the white dwarf resembles a recycled pulsar.