What binary systems are the most likely sources for periodically repeating FRBs?

Abstract

ABSTRACT The newly discovered 16.35-d period for repeating FRB 180916.J0158+65 provides an essential clue for understanding the sources and emission mechanism of repeating fast radio bursts (FRBs). Many models propose that the periodically repeating FRBs might be related to binary star systems that contain at least one neutron star (NSC-FRB system). It has been suggested that the neutron star ‘combed’ by the strong wind from a companion star might provide a solution. Following the binary comb model, we use the population synthesis method to study in detail the properties of the companion stars and the nature of NSC-FRB systems. Our main findings are as follows: (1) the companion star is most likely to be a B-type star; (2) the period of 16 d of FRB 180916 happens to fall in the most probable period range, which may explain why FRB 180916 was the first detected periodically repeating FRB, and we expect to observe more periodically repeating FRBs with periods around 10–30 d; and (3) the birth rate for the NSC-FRB system is large enough to fulfill the event rate requirement set by the observation of FRB 180916, which supports the proposal that the NSC-FRB can provide one significant channel for producing periodically repeating FRBs.