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White Dwarf-Red Dwarf Pair Identified as Radio Transient Source

6/23/2026

Summary

Story summary

University of Sydney researchers identified ASKAP J174508.9-505149 as a white dwarf accreting from a companion, confirming a magnetic cataclysmic variable.
Spectroscopy showed hydrogen Balmer and strong HeII lines, indicating an orbital period of ~1.345 hours and radio pulses that repeat every 368 hours.
The companion’s mass (~0.096 M?) and radius (~0.13 R?) match an M6-class red dwarf, giving the strongest evidence that magnetic cataclysmic variables cause long-period radio transients.

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Story summary

University of Sydney researchers identified ASKAP J174508.9-505149 as a white dwarf accreting from a companion, confirming a magnetic cataclysmic variable.
Spectroscopy showed hydrogen Balmer and strong HeII lines, indicating an orbital period of ~1.345 hours and radio pulses that repeat every 368 hours.
The companion’s mass (~0.096 M?) and radius (~0.13 R?) match an M6-class red dwarf, giving the strongest evidence that magnetic cataclysmic variables cause long-period radio transients.