Letters of Intent for 2015

LoI 2015-189
Focus Meeting: Connecting Solar and Stellar Variability

Date: 3 August 2015 to 14 August 2015
Location: Honolulu, United States
Contact: Natalie Krivova (natalie@mps.mpg.de)
Coordinating division: Division E Sun and Heliosphere
Co-Chairs of SOC: Natalie Krivova (Max Planck Institute for Solar System Research)
Alexander Shapiro (Physikalisch-Meteorologishes Observatorium Davos, World Radiation Center)
Gibor Basri (Astronomy Department, University of California)
Philip Judge (High Altitude Observatory, National Center for Atmospheric Research)
Chair of LOC: ()



1. Stellar variability on rotational time scales; Kepler and Corot measurements.

2. Stellar variability on activity cycle time scales; ground based observations.

3. Measurements of solar irradiance variability.

4. Physical mechanisms and models of solar and stellar variability.

5. Comparability of solar and stellar variability measurements.

6. Is the Sun a solar-type variable?

7. The photometric signature of magnetic activity: darker or brighter?

8. Constraining dynamo models using solar and stellar variability records.

9. Influence of solar and stellar variability on Earth and other planets.

10. Stellar variability as a limiting factor for detectability of extra-solar planets.



This meeting aims to bring together solar and stellar researchers whose goal is to understand magnetic variations in the Sun and stars. Regular space-borne measurements since 1978 have revealed significant solar irradiance variations on up to multi-decadal time scales. Variability on time scales of several hours and longer is thought to be linked to the magnetic activity of the Sun. Concurrently, ground-based photometric measurements of Sun-like stars uncovered similar variations, although their variability patterns show a much wider variety.

So far both the solar and stellar variability communities have had limited interaction, although both would greatly profit from closer collaboration. Solar scientists by broadening their models to reproduce not just the variability of one star, the stellar astronomers by gaining more insights into the physical causes of stellar variability. Such an interaction would also help to understand whether the observed patterns of stellar variability are compatible with the solar paradigm, and dismiss certain physical classes of dynamos. This is not only important for solar and stellar physics, but solar irradiance variations are critical for climate models, and stellar brightness variations are one of the critical limitation on detectability of extrasolar planets.

The unprecedented precision of stellar photometry achieved by the recent Kepler and Corot space missions has opened a door for linking solar and stellar data and studying stellar variability in the solar context. It is timely that the two communities share their expertise and plan future collaborations. Since IAU General Assemblies are widely attended by the both communities, a Focus meeting during the IAU GA in Honolulu is a unique opportunity to trigger such a joint discussion.