Astronomers have discovered a dead star spinning once every eight minutes and sending out mysterious radio pulses while orbiting a companion star virtually identical to our Sun.
Located more than 5,000 light-years from Earth, the system is designated GPM J071507−114153. The findings were published on November 12, 2026, in the journal Nature Astronomy in a study titled “A long-period transient with a Sun-like companion”.
GPM J071507−114153 is the first system identified where a white dwarf orbits a G-type, sun-like star. The system belongs to a group of astronomical objects known as long-period transients (LPTs), which produce radio signals that switch on and off over intervals lasting from minutes to hours. About a dozen LPTs have been detected since the research team found the first in 2021.
Lead author Sam McSweeney made the discovery while working at ICRAR and is now a commissioning scientist with the Square Kilometre Array Observatory (SKAO). The discovery was made by researchers at the Curtin University branch of the International Centre for Radio Astronomy Research (ICRAR).
McSweeney said: “This is the first time the pulses are clear enough to see the white dwarf moving in its orbit around its companion, so we know that the pulsations are coming from a region close to the white dwarf, or possibly even from the white dwarf itself.”
The Pawsey Supercomputing Research Centre processed more than 100 hours of raw radio data from the MWA, while South Africa’s MeerKAT radio telescope determined the precise position of the LPT. The research team initially detected the system in a survey using the Murchison Widefield Array (MWA) to scan the Milky Way visible from Australia.
Following radio detection, the system was confirmed using the W. M. Keck Observatory on Maunakea in Hawai’i, where visible light follow-up confirmed that the companion star is a G-type star.
Both MeerKAT and the MWA serve as precursors for the Square Kilometre Array (SKA). McSweeney said that making such discoveries with precursor telescopes indicates how many more star systems will be found once SKA telescopes are completely built.
Natasha Hurley-Walker, a team member at ICRAR, said: “As a bonus, we also saw the white dwarf moving behind a region with a strong magnetic field, most likely a ‘stellar prominence,’ which is a large loop of plasma erupting from a star’s surface. It’s amazing that by using radio wavelengths we can detect the storms on a star over 5,000 light-years away.” The radio pulses enabled the research team to detect stellar flares erupting on the sun-like star.
Researchers conclude that the phenomenon is governed by the white dwarf’s magnetic field strength and binary orbital geometry rather than the spectral type of the companion. This implies that the total population of long-period transients in the Milky Way is likely far larger than estimates based exclusively on white dwarf and red dwarf pairings.
Earlier coverage: Astronomers Trace Mystery Radio Signals Back to Cosmic Odd Couple of White Dwarf and Sun-Like Star