A 3.56-hour white dwarf (WD) - M dwarf (MD) close binary system, AR Scorpii, was recently reported to show pulsating emission in radio, IR, optical, and UV, with a 1.97-minute period, which suggests the existence of a WD with a rotation period of 1.95 minutes. We propose a model to explain the temporal and spectral characteristics of the system. The WD is a nearly perpendicular rotator, with both open field line beams sweeping the MD stellar wind periodically. A bow shock propagating into the stellar wind accelerates electrons in the wind. Synchrotron radiation of these shocked electrons can naturally account for the broad-band (from radio to X-rays) spectral energy distribution of the system.
@article{arxiv.1609.02508,
title = {A Model of White Dwarf Pulsar AR Scorpii},
author = {Jin-Jun Geng and Bing Zhang and Yong-Feng Huang},
journal= {arXiv preprint arXiv:1609.02508},
year = {2017}
}