Variability of Solar/Stellar
Magnetic Activity

A COOL STARS 19 Splinter Session

Part I: 7 June 2016, 14:00 - 17:00
Part II: 9 June 2016, 14:00 - 17:00

Session organizers

Scientific Motivation

The richness of solar observations, for which continuous monitoring is now available at extremely high spatial resolution and throughout the electromagnetic spectrum (e.g., HINODE, SDO), is complemented by a wealth of new spectro-polarimetric information at increasing temporal resolution in the new era of statistical studies of unprecedentedly huge samples of stars observed by space-borne telescopes like KEPLER and COROT

Together with the results of advanced theoretical and computational tools and the availability of massively-parallel supercomputers, these new data are rapidly changing our view of stellar magnetic activity and variability throughout stellar evolution.

Solar-like stars are known to show chromospheric activity similar to that on the Sun, e.g. in the Ca II H and K emission indicators. Magnetic activity shows erratic, multi or single periodic behavior, interrupted by long quiescent periods (grand minima). What is the origin of this broad range of variability in stellar activity and how does it relate to solar variability and activity?

In solar-like stars, the cyclic activity is ascribed to a dynamo mechanism maintained through differential rotation at the tachocline. However, the tachocline moves towards increasing depths with later spectral types, disappearing around spectral-type M4. Thus, a direct comparison between the stellar activity in solar-type with lower-mass stars is essential for the understanding of the effect of stellar mass on the resulting magnetic activity through a dynamo mechanism.

This Splinter is aimed at offering a synthetic view of the recent progresses in the domain of variability of stellar magnetism from different perspectives. We invite astrophysicists to present their latest results on this topic, particular in relation to the solar-stellar connection and the intimate interplay between magnetic activity and variability of our Sun and cool stars.


This splinter session will be split over two afternoons, Tuesday 7 June and Thursday 9 June. The full programme of the splinter session can be downloaded here.

In Session 1 (Tuesday 7 June), we will address the nature of solar/stellar magnetic variability based on observations of the Sun and other cool stars. We will focus on solar/stellar brightness variations on different time scales as well as at on the properties of solar/stellar magnetic fields

In session 2 (Thursday 9 June), we will address the origin and evolution of stellar magnetic activity in light of the latest results from survey and dynamo theory.

Click on the table below to expand the detailed programme for the various sessions:

Invited speakers


Click here to access all slides from this splinter session's presentations (format: PDF).


Questions about this splinter session can be directed to Damian Fabbian or Rosaria Simoniello.

If you experience problems with the website, please send an e-mail to Remo Collet.