27 septembre 2022
Speaker : Marcel Agueros (Univ. de Columbia)
Title: Studying Low-Mass Stars in the Era of Surveys: Data, Models, and Surprises
Abstract: Stellar ages are notoriously difficult to measure accurately for main-sequence low-mass stars, which limits our ability to address questions ranging from the evolutionary state of exoplanets to the chemical history of the Galaxy. Gyrochronology, which uses stellar rotation as a proxy for age, is a promising solution to this quandary. Unfortunately, however, empirical and theoretical models of the age-rotation relation have been hampered by a lack of rotational measurements for large numbers of low-mass stars with a wide range of well-known ages. We are still far from being able to describe fully the evolution of rotation for low-mass stars, or from being able to use rotation measurements to estimate accurately the ages of isolated field stars. I will summarize recent ground-based and space-based work to characterize the rotational behavior of G, K, and M dwarfs in open clusters ranging in age from 125 Myr (the Pleiades) to 3 Gyr (Ruprecht 147), and then compare these data to each other and to models for stellar spin-down to appraise our current understanding of the age-rotation relation. I will also touch on an on-going survey targeting newly discovered single-aged stellar populations to address the broader age-rotation-activity relation.