Scientists detect mysterious radio signal from a star 11.5 light-years from Earth

Astronomers have recorded an unusual radio signal from the red dwarf star GJ 725A, located approximately 11.5 light-years from Earth. The origin of this radiation, observed at a frequency around 45 megahertz, remains unknown. Scientists speculate that its appearance could be linked to the star's magnetic activity or its surrounding planets.

The research was conducted by an international team of astronomers based on observations using the LOFAR radio telescope. The signal was detected in the 42–50 megahertz range and persisted throughout a one-hour observation period. However, it was not recorded again in subsequent observations.

Scientists also determined that the radio signal has strong circular polarization, with a polarization degree of 74 percent. Astrometric analysis confirmed that the source of the radiation is the star GJ 725A, rather than its companion star.

Researchers are proposing three possible hypotheses to explain the origin of the signal.

The first hypothesis suggests that the radio signal may be related to auroras on a large, as-yet-undiscovered gas giant planet orbiting the star at a long distance. Such a planet would need to have a strong magnetic field. Scientists compare this process to the magnetic interaction between Jupiter and its volcanically active moon, Io.

The second possibility suggests that the signal resulted from the star's own magnetic activity. However, GJ 725A is considered a relatively quiet star, rotating on its axis approximately once every 103 days. Therefore, this hypothesis also requires further investigation.

The third hypothesis suggests that the radio signal may have been produced by a magnetic interaction between the star and a previously known rocky planet called GJ 725Ab. This planet completes a full orbit around the star approximately every 11.2 days and has a mass 2.8 times that of Earth. However, it is not yet clear whether such a planet's magnetic properties would be sufficient to generate the observed strong radio signal.

To determine the true source of the signal, scientists plan to conduct regular radio frequency monitoring of the GJ 725A system, as well as additional research in X-ray and ultraviolet ranges.

The research results were published on the arXiv platform on November 5, 2026. The article has been accepted for publication in the journal Astronomy & Astrophysics.