Astronomers Solve a Cosmic Whodunit, Pinpointing Radio Bursts to a White Dwarf

Astronomers have identified the source of a mysterious, repeating radio signal coming from a binary star system 5,000 light-years away. The system, named GPM J071507−114153, features a rapidly spinning white dwarf—a dense, dead star—orbiting a sun-like star. The white dwarf pulses with radio waves every eight minutes, a rare phenomenon seen in only about a dozen similar systems classified as long-period transients. For years, it was unclear whether the radio pulses originated from the white dwarf or its companion star in such systems.

This discovery is a breakthrough because, for the first time, the radio pulses were clear enough to track the white dwarf's orbital motion, definitively proving the signal comes from a region very close to, or from, the white dwarf itself. This gives scientists a crucial new piece of evidence for understanding the physics of these enigmatic long-period transients. As a bonus, the radio data even allowed the team to detect stellar flares erupting on the companion star, showcasing the powerful diagnostic capabilities of modern radio telescopes like South Africa's MeerKAT.