Astronomy Colloquium

Main sequence stars with masses below approximately 0.35 solar masses (red dwarfs, or M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. These low-mass stars are the most common type of star in the galaxy, but a lack of observational constraints at ages beyond 1 Gyr has hampered studies of rotational evolution and magnetic activity. To address this, we have made new measurements of rotation and magnetic activity in nearby, field-age M dwarfs. I will discuss the relationships we see between age, rotation, and activity, and what they mean for rotational evolution, starspot properties, and the magnetic dynamo. Upcoming ground-based instruments and space-based surveys offer exciting prospects for continuing the study of cool stars, as well as the exoplanets that orbit them.