A joint research team led by Dr. Abdusattar Kurban from the Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences (CAS) has proposed a new model which attributes periodic repeating fast radio bursts (FRBs) to the interaction of a neutron star (NS) with its planet in a highly elliptical orbit.

The study was published in The Astrophysical Journal. Researchers from the Nanjing University, Purple Mountain Observatory of CAS, and the Institute of High Energy Physics of CAS were also involved in the study.

FRB is a mysterious radio burst that releases extremely high energy in milliseconds. Since its first discovery in 2007, the number has increased to hundreds. Some of these FRBs will burst only once, while others will erupt repeatedly.

In a highly elliptical orbit, a planet is very close to the neutron star at the near star point of the planetary orbit. Every time the planet passes through this point, it will be elongated and partially torn apart if the tidal force is greater than the self-gravity of planet. In these processes, clumps of several kilometers in size will be produced.

"After being torn apart, the clumps move around the neutron star. Neutron stars produce stellar winds like the Sun. When the wind of the neutron star interacts with the clumps moving around, extremely strong radio radiation will be generated," said Dr. Kurban.

The researchers found that when the clump was in the line of sight between the Earth and the neutron star, the FRBs could be detected, and when it deviated from the line of sight, the signal disappeared. The FRBs would show the characteristics of repeated occurrence when the debris continuously passed through our line of sight.

The clumps lost energy under the influence of gravity when they orbited the neutron star, and their orbits would decay rapidly. Therefore, no FRBs would be observed from these older fragments.

By comparing the calculated results with the observed characteristics of two known periodic repeating FRBs (FRB121102 and FRB180916, with a burst period of about 160 days and 16 days, respectively), they found that the model could explain the basic characteristics of the two repeating FRBs.

The researchers will continue to study the possible physical processes after the tidal disruption.