Speaker
Description
All stars with an outer convection zone are magnetically active at some level, with the amount of activity depending on stellar parameters, e.g. the effective temperature and the rotation rate. By far the best studied such star is the Sun. While investigating other stars allows studying stellar activity across a broad range of stellar properties, the Sun provides us with the unique opportunity of resolving a stellar surface and atmosphere in detail so that the physical processes taking place there can be probed close to the spatial and temporal scales at which they occur. It is from the Sun that we know that, excepting differential rotation and meridional circulation that drive the solar dynamo, the most important interaction for its activity and variability takes place between the magnetic field and surface convection. This interaction leads to an assortment of magnetic features at the solar surface, whereby the properties of such features depend on the amount of magnetic flux present at their location and in their vicinity. Recent years have seen considerable progress in our knowledge and understanding of solar variability and activity thanks to new instruments, telescopes and space missions as well as improved numerical simulations. On the stellar front, highly sensitive observations carried out by space missions aiming to detect and characterize exoplanets have led to an explosion in observations of stellar variability. The advances in understanding and quantitatively modelling solar variability have also paved the way to a better understanding of the variability seen in other sun-like stars. An introductory overview and selected highlights of recent results will be presented in this talk.