Optical Transients from Fast Radio Bursts Heating Companion Stars in Close Binary Systems

• Published in: The Astrophysical journal Vol. 920; no. 1; pp. 34 - 40
• Main Author: Yang, Yuan-Pei
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01-10-2021; IOP Publishing
• Subjects: Astrophysics; Binary stars; Brightness temperature; Companion stars; Galaxies; Globular clusters; Globular star clusters; Luminosity; Magnetars; Main sequence stars; Neutron stars; Orbits; Radiation; Radiation effects; Radio bursts; Radio transient sources; Stellar age; Transients (astronomy)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ac2146

Abstract
Fast radio bursts (FRBs) are bright radio transients with short durations and extremely high brightness temperatures, and their physical origins are still unknown. Recently, a repeating source, FRB 20200120E, was found in a globular cluster in the very nearby M81 galaxy. The associated globular cluster has an age of ∼9.13 Gyr, and hosts an old population of stars. In this work, we consider that an FRB source is in a close binary system with a low-mass main-sequence star as its companion. Due to the large burst energy of the FRB, when the companion star stops the FRB, its surface would be heated by the radiation-induced shock, and make reemission. For a binary system with a solar-like companion star and an orbital period of a few days, we find that the reemission is mainly at an optical band, with delays of a few seconds after the FRB. Its luminosity is several times larger than the solar luminosity, and the duration is about hundreds of seconds. Such a transient might be observable in a future multiwavelength follow-up observation for Galactic FRB sources.