Title: Angular Momentum Evolution of Solar-type Stars and Implications for Gyrochronology
Abstract:
A detailed understanding of the assembly history and rate of chemical enrichment in the Milky Way requires accurate ages for vast numbers of stars.  Standard age-dating techniques have significant degeneracies and other limitations, and in any case are mostly limited to the tiny minority of stars in bound clusters.  Data from the Kepler and K2 surveys, along with ground-based studies, show that stellar rotation rates could potentially be exploited to determine ages of field stars since rotation declines with age; this method is called gyrochronology.  Several groups have advocated a purely empirical gyrochronology, essentially fitting simple mathematical expressions to rotation/age data, but in this talk I argue that the power of rotation studies lies in their use for calibrating (or rejecting) proposed physical mechanisms for internal angular momentum transport and angular momentum loss through magnetized winds.
I will review the available data, discuss several important selection biases, and will present the results of a detailed Bayesian modeling exercise to show how well a gyrochronology might work in the most favorable cases.  I will also discuss whether evidence for saturation of wind loss or of internal angular momentum transport is properly justified in a statistical sense.