Angular momentum evolution of cool stars: Toward a synthesis of observations and theory before and after the ZAMS



The coexistence of fast and slowly rotating cool stars in ZAMS clusters – forming distinct sequences in the color vs. rotation period plane – is providing clues to differences in their pre main-sequence angular momentum evolution. This Cool Stars 17 splinter was dedicated to a discussion of new observational and theoretical results that may help discriminate between proposed mechanisms for early angular momentum regulation and help us explain the observed ZAMS dichotomy