More than 5,000 light-years away, an unusual stellar system sends radio pulses toward Earth roughly every eight minutes. Astronomers have now linked those signals to an unlikely pair: a white dwarf, the compact remains of a dead star, and a companion resembling our Sun.
The discovery, described in a study published in Nature Astronomy on November 12, 2026, offers a new example of a puzzling class of objects called long-period transients. More importantly, it gives researchers a way to investigate how two very different stars can produce repeating radio emission.
Two Stars at Different Stages of Life
The system is called GPM J071507−114153. Its white dwarf and Sun-like companion illustrate two stages in the lives of stars.
A star like our Sun spends most of its life producing energy by fusing hydrogen into helium in its core. Eventually, its fuel supply and internal structure change. It expands into a red giant and later sheds its outer layers, leaving the exposed core behind.
That remaining core becomes a white dwarf. Although roughly Earth-sized, a white dwarf contains an enormous amount of matter compressed into a small volume. Calling it “dead” means that it has finished the main stages of its nuclear-burning life; it can remain extremely hot and continue radiating energy as it cools.
The companion in this newly studied system is a G-type star, the same broad stellar category as the Sun. That classification does not mean it is identical to our star or has a planetary system like ours.
Why Every Eight Minutes?
The measured radio repetition period is 7.9 minutes. Researchers interpret this as the white dwarf’s rotation. A separate variation lasting about 1.3 days is interpreted as the time the stars take to orbit each other. The rapid pulses and the slower orbital cycle are therefore different clocks within the same system.
Regular flashes are familiar in astronomy. Many pulsars are rapidly rotating neutron stars whose radiation beams sweep across our line of sight, rather like a lighthouse. An observer detects a pulse whenever the beam points toward Earth.
A white dwarf is a different kind of stellar remnant from a neutron star. Nevertheless, white dwarfs can also display pulsar-like behaviour. The previously discovered system AR Scorpii, for example, contains a white dwarf paired with a cool, low-mass star. Its existence showed that a rotating neutron star is not the only stellar object capable of producing this kind of activity.
The important question is therefore not simply why a star appears to flash. It is what generates the emission and how the companion contributes.
How Astronomers Found the Source
According to the discovery announcement from ICRAR, the team first identified the source using the Murchison Widefield Array in Western Australia. Follow-up observations with South Africa’s MeerKAT radio telescope narrowed down its position, while optical observations from the W. M. Keck Observatory identified the Sun-like companion.
Researchers also analysed more than 100 hours of radio observations. Changes in pulse arrival times allowed them to trace motion associated with the white dwarf, placing the emitting region close to that remnant.
Discovering such objects requires watching how the sky changes. A source that briefly brightens can be difficult to recognise in an image that combines a long stretch of observations.
A separate study developing search methods for long-period transients illustrates the challenge. Researchers examined how brightness changed within radio images, then filtered out false candidates caused by instrumental effects and Earth’s ionosphere. Among 336 final candidates, seven were genuine transient sources. That result shows why a promising flash needs careful checking before it becomes an astronomical discovery.
A Magnetic Fingerprint From Another Star
The new research reports rapid changes in the radio signal’s polarization-related properties when the white dwarf passes behind its companion. These changes are consistent with the radiation travelling through the companion’s hot, magnetised outer atmosphere.
The researchers conclude that interaction with the companion is important in producing the radio pulses in white-dwarf binary long-period transients.
This gives the signals a second use: they can probe material around another star. Instead of relying only on light emitted by the companion, astronomers can examine how radiation changes while passing through its surroundings.
That distinction matters. A signal can carry information about both its source and the material encountered along its journey. Here, the repeating pulses provide a moving probe of a stellar environment that cannot be examined directly at close range.
Why This Discovery Matters
Earlier confirmed white-dwarf binaries in this class included cooler M-dwarf companions. The new system extends the picture to a G-type star in a substantially longer orbit. Models must therefore explain a wider range of stellar partnerships.
It does not follow that every long-period transient has the same explanation. Establishing how one system works is a step toward understanding the population, rather than proof that all its members are identical.
The discovery also suggests a useful direction for future searches: look for more systems, compare their companions and measure how their pulses change throughout an orbit.
Each additional example can test whether the same physical process operates across different environments. For now, this distant pair offers something particularly valuable: a repeating radio signal that helps astronomers study both a stellar remnant and the atmosphere of the star beside it.
