Stellar activity cycles and contribution of the deep layers knowledge

TL;DR

This paper reviews how asteroseismology and space missions like CoRoT and Kepler are advancing our understanding of stellar magnetic activity cycles and the underlying dynamo processes, revealing new insights into stellar variability.

Contribution

It highlights recent results from spectroscopic and asteroseismic studies, emphasizing the role of space missions in uncovering stellar activity mechanisms and deep layer contributions.

Findings

Asteroseismology provides new insights into stellar magnetic activity.

Space missions have detected short activity cycles in stars.

Understanding of stellar dynamo processes is significantly improved.

Abstract

It is believed that magnetic activity on the Sun and solar-type stars are tightly related to the dynamo process driven by the interaction between rotation, convection, and magnetic field. However, the detailed mechanisms of this process are still incompletely understood. Many questions remain unanswered, e.g.: why some stars are more active than others?; why some stars have a flat activity?; why is there a Maunder minimum?; are all the cycles regular? A large number of prox- ies are typically used to study the magnetic activity of stars as we cannot resolve stellar discs. Recently, it was shown that asteroseismology can also be used to study stellar activity, making it an even more powerful tool. If short cycles are not so un- common, we expect to detect many of them with missions such as CoRoT, Kepler, and possibly the PLATO mission. We will review some of the latest results obtained with spectroscopic measurements. We will show how asteroseismology can help us to better understand the complex process of dynamo and illustrate how the CoRoT and Kepler missions are revolutionizing our knowledge on stellar activity. A new window is being opened over our understanding of the magnetic variability of stars.