Chinese Astrophysicists Uncover Compelling Evidence of Binary Star Origins for Fast Radio Bursts

A team of Chinese astrophysicists has unveiled significant new evidence supporting the theory that at least a portion of Fast Radio Bursts (FRBs) originate within binary star systems. This breakthrough centers on the detection of a sudden, rapid, and reversible spike in the Faraday Rotation Measure (RM) of a repeating FRB. Scientists interpret this dramatic fluctuation as a direct consequence of the radio signal passing through the dense, magnetized plasma emitted by a nearby companion star.

While the findings were officially published in the prestigious journal Science in January 2026, the foundational observations were captured earlier, in December 2023. The research utilized the immense capabilities of the Five-hundred-meter Aperture Spherical radio Telescope (FAST), located in China’s Guizhou Province. Since June 2022, researchers had been conducting a continuous monitoring campaign of the repeating source known as FRB 20220529, which is situated approximately 2.9 billion light-years away from Earth.

In December 2023, the recorded RM for FRB 20220529 experienced a massive surge, increasing by roughly 20 times compared to its average variability before returning to baseline levels within a two-week window. This specific source is located within a disk galaxy at a redshift of 0.1839. Prior to this event, the RM for FRB 20220529 had remained remarkably stable for 17 months, showing only minor fluctuations of approximately 21 ± 96 rad m⁻². The sudden escalation to 1976.9 rad m⁻², which represents a deviation exceeding twenty times the standard norm, suggests the signal encountered a highly magnetized and dense clump of matter, likely a coronal mass ejection resulting from a stellar flare.

This ambitious scientific project involved a collaborative effort between astronomers from the Purple Mountain Observatory (PMO) of the Chinese Academy of Sciences (CAS), the University of Hong Kong (HKU), and Yunnan University, alongside Professor Duncan Lorimer from West Virginia University. The research team concluded that such a violent shift in the Faraday Rotation Measure is fundamentally inconsistent with existing models that rely on isolated neutron stars. Instead, the data strongly validates the binary system model for the source of FRB 20220529. This discovery represents the first instance of obtaining such direct observational proof for the binary origin of cosmological Fast Radio Bursts.

Often referred to as "China's Sky Eye" or "Tianyan," the FAST telescope’s unparalleled sensitivity was instrumental in identifying this specific source. The Faraday Rotation Measure acts as a precise cosmic magnetic probe, allowing scientists to calculate the properties of magnetized plasma along the path of radio wave propagation. While previous scientific consensus often favored isolated magnetars as the primary source of these bursts, these new results shift the focus toward the complex dynamic interactions found in binary systems. Ongoing, long-term observation of repeating FRBs will be essential to determine how common these binary configurations are among such mysterious cosmic phenomena.