“Detection of Fine-structured Radio Bursts during a Superflare on EQ Peg” (2026), by Zhanhao Zhao et al. Physics and Astronomy research paper. Original abstract below, unchanged. A free PDF is available.

Detection of Fine-structured Radio Bursts during a Superflare on EQ Peg

Zhanhao Zhao, Xin Cheng, Yuankun Kou et al. · November 5, 2026 · Physics and Astronomy

Abstract

Superflares are frequently observed on magnetically active stars, particularly on active M dwarfs, thereby influencing the habitability of nearby exoplanets. However, the causes of superflares remain unclear. Here, combining FAST and TESS, we detected a finely structured decimetric radio burst appearing as groups of spikes during a white-light superflare (total bolometric energy ∼ 10 33 erg) on the M dwarf binary EQ Peg on 2022 September 8. The most significant ones appeared near the peak time of the optical flare and lasted for about 100 s. The radio spikes present extremely high brightness temperatures (≳10 13 K) and high degrees of circular polarization (∼0.84 ± 0.16), indicating their origin in a coherent emission process, most likely the electron cyclotron maser. Based on Zeeman Doppler imaging measurements of EQ Peg, we further locate the sources of the radio spikes, including their heights and latitudes, under the assumption of a large-scale dipolar magnetic field configuration. The results provide strong evidence for finely structured decimetric radio bursts generated by stellar flares and shed light on the origin of superflares.

Free PDF DOI: 10.3847/1538-4357/aeb003