Flaring activities of fast rotating stars have a solar-like latitudinal distribution

¹ Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
² Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206, China
³ School of Astronomy and Space Science, Nanjing University, Nanjing 210093, China
⁴ School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
⁵ State Key Laboratory of Solar Activity and Space Weather, Beijing 100190, China

^⋆ Corresponding author; yhq@nao.cas.cn

Received: 22 November 2024
Accepted: 25 January 2025

Abstract

Context. The dynamo theory has always been one of the biggest mysteries in stellar physics. One key reason for its uncertainty is poor knowledge of the dynamo process on stars other than the Sun. The most important observed feature of the solar dynamo is that active regions only appear at low latitudes, which provides a crucial constraint to the dynamo theory, while with Doppler imaging, the current technique to spatially resolve the stellar hemisphere, it is difficult to distinguish the equatorial region. As a consequence, the latitudinal distribution of active regions (LDAR) of stars is ambiguous and controversial, mainly due to the limitations of the current technique for spatially resolving the stellar surface.

Aims. Fast rotating stars, which are young and active, are thought to operate with a different dynamo process than the Sun. We study their LDAR and compare them with the Sun to reveal the underlying dynamo process.

Methods. Flares are drastic and observational activity events that occur in active regions. Here, we propose a new method for studying how the apparent flaring activity varies with respect to the inclination to determine the LDAR of fast rotating stars.

Results. We find that the LDAR of fast rotating stars is consistent with that of the Sun, contrary to expectations. Our results provide a crucial constraint to the stellar dynamo, indicating that the solar-like dynamo also applies to fast rotating stars, and even spans different stages of their evolution.