Ricky Egeland (High Altitude Observatory): Patterns of Long-term Variability in the Sun and Stars
Recent observations by McIntosh et al. stress the importance of the extended magnetic solar cycle as the fundemental pattern underlying the more prevalent sunspot cycle. I will discuss new synoptic observstions with Hinode that seek to illuminate the behavior of the extended solar cycle at the smallest observable scales. In contrast to the detailed observations required to reveal the extended solar cycle, the sunspot record and other Sun-as-a-star magnetic proxies like Ca II HK irradiance can be thought of as a rough global-scale observation of the Sun's magnetic variability. For more distant stars, these types of observations are all that are available. Stellar Ca II HK observations show that most Sun-like stars have either more complex variability than the Sun, or none at all, and that the nearly-regular cyclic variability the Sun manifests is due to its nearly maximal Rossby number. Is our zero-dimensional view of stellar magnetism enough to understand the fundamentals of their underlying dynamos?