Understanding the physical mechanisms of solar variability and its effect on Earth and the planets is a central and long-standing problem of astronomy and astrophysics. Variability of a similar nature has been observed in other stars, and investigating their similarities and differences is essential to helping us understand the underlying mechanisms and their impacts on planets. During the past decade multi-wavelength data from several solar and stellar space missions, together with ground-based observations, have provided tremendous amounts of new information about the physical processes on the Sun and solar-type stars. Solar observations have revealed interesting connections between the cyclic variations of the structure, interior dynamics, surface magnetism and coronal phenomena, but it is still unclear where and how magnetic fields are generated in the Sun, and why it has a regular 22-year magnetic cycle. IAU Symposium 264 discusses key observational results, new theoretical ideas and models which address these subjects.
Preface; Organizing committee; Conference participants; 1. Introduction: the Sun and stars as the primary energy input in planetary atmospheres; 2. Observations of solar and stellar variability; 3. Solar and stellar cycles and variability on century timescale; 4. Magnetic activity and dynamo mechanisms; 5. Physical mechanisms of solar and stellar variability; 6. Effects on space weather and climate; 7. Effects of magnetic activity on planet formation and evolution; 8. Impact of solar and stellar variability on planetary atmospheres and climate; 9. Current and future space missions and ground-based observing programs; 10. Summary and conclusions; Author index; Subject index.