Astronomers have traced a mysterious radio signal back to a cosmic odd couple comprised of a dead star, a white dwarf, and its stellar companion, a sun-like star.

The white dwarf in the newly discovered system, designated GPM J071507−114153 and located around 5,000 light-years away, spins once every eight minutes, sending out radio pulses. These radio pulses have been seen from binary systems with smaller and cooler red dwarf stars before, but rarely from a system like GPM J071507−114153.

GPM J071507−114153 belongs to a class of celestial objects called long-period transients (LPTs) known to produce radio signals that switch on and off over intervals of minutes or hours. Around a dozen LPTs have been detected since the team behind this research found the first in 2021. Several previously discovered LPT systems contain a white dwarf and a companion star, but it has been unclear which of the two stars was generating the radio pulses.…