A newly identified stellar system may help explain one of astronomy’s more puzzling phenomena: long-period radio transients, or LPTs. These rare objects emit powerful bursts of polarized radio waves at intervals ranging from minutes to hours, but scientists have struggled to determine what produces them.
Researchers now report that ASKAP J174508.9-505149, a distant binary star system discovered through radio observations, appears to be an accreting white dwarf binary capable of generating both radio and X-ray emissions. The findings strengthen evidence that at least some LPTs originate from compact white dwarf systems.
Discovery of ASKAP J1745-5051
The object, known as ASKAP J1745-5051, was first detected using the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope during a search for circularly polarized radio sources.
Follow-up observations with South Africa’s MeerKAT radio telescope allowed astronomers to refine the system’s location and identify an optical counterpart through data from the European Space Agency’s Gaia mission. The object appeared relatively faint but displayed unusual optical characteristics associated with highly magnetic stellar systems.
Optical Signatures Reveal a Magnetic Binary
Spectroscopic observations conducted with telescopes in Chile revealed strong hydrogen and helium emission lines alongside a flat optical spectrum with a blue excess. These are considered hallmark traits of magnetic cataclysmic variables — compact binary systems in which a magnetized white dwarf pulls material from a nearby companion star.
Cataclysmic variables are already known for producing energetic outbursts and intense magnetic activity. However, ASKAP J1745-5051 stands out because it also emits coherent, highly polarized radio bursts similar to those seen in long-period radio transients.
A Fast Orbit and Repeating Radio Bursts
Researchers determined that the binary system completes an orbit roughly every 1.37 hours, placing it near the shortest known orbital periods for cataclysmic variables.
The radio bursts repeat on a schedule that closely matches the orbital motion of the system. Scientists also found that the bursts tend to occur near orbital conjunctions — moments when the stars align from Earth’s perspective.
This repeating behavior resembles radio patterns previously observed in systems such as AR Scorpii, another unusual white dwarf binary that emits strong radio signals. ASKAP J1745-5051, however, has an even shorter orbital period than several other known LPT candidates.
X-Ray Activity Supports Accretion Theory
The system also showed evidence of an ongoing X-ray outburst, suggesting that material from the companion star is actively falling onto the white dwarf’s surface.
This accretion process is believed to play a key role in generating the observed radio emissions. Researchers noted that the system’s radio luminosity is dramatically stronger than radio emissions previously detected from most cataclysmic variables.
Some radio-emitting white dwarf systems have been identified before, but none were known to produce such bright, periodically repeating bursts on this scale.
Why Long-Period Radio Transients Matter
Long-period radio transients have become an important topic in astrophysics because they do not fit neatly into traditional categories of cosmic radio sources.
Some scientists previously proposed slowly rotating magnetars — highly magnetized neutron stars — as a possible explanation. Others suggested rapidly orbiting white dwarf binaries. The discovery of ASKAP J1745-5051 provides some of the strongest observational support so far for the white dwarf binary hypothesis.
Researchers say the system could represent an evolutionary stage connected to other rare magnetic binaries, potentially offering insight into how compact stellar systems evolve over time.
Expanding the Search for Rare Stellar Systems
The discovery also highlights the growing role of next-generation radio observatories in detecting unusual transient events across the sky.
Facilities such as ASKAP and MeerKAT are capable of continuously monitoring large areas of space, allowing astronomers to identify rare objects that older surveys may have missed.
As more long-period radio transients are discovered, scientists hope to determine whether magnetic white dwarf binaries account for most of these mysterious signals or whether multiple types of objects are involved.
For now, ASKAP J1745-5051 offers one of the clearest links yet between periodic radio bursts and compact white dwarf systems, providing a major step toward understanding a class of cosmic phenomena that has puzzled astronomers for years.
Abigail Prescott is a contributor to Campuslately.com, covering a wide range of topics including news, politics, business, technology, sports, entertainment, and lifestyle. She focuses on delivering clear, accurate reporting and useful information that helps readers stay informed about current events and emerging trends. With a reader-first approach, Abigail highlights stories that matter, providing balanced coverage and accessible insights on issues relevant to everyday audiences.
