# TESS Program G04217

Title: When Do Stars Converge Onto Slowly Rotating Sequences? A Stellar Rotation Survey Of Young Coeval Populations

PI: Curtis, Jason - Columbia University

Type: SMALL

Summary: Gyrochronology is a promising yet flawed clock. Recent studies of open clusters revealed that stars do not spin down continuously. Instead, once stars converge onto tight sequences of slowly rotating stars, they temporarily stall for an unknown but extended period of time. This phenomenon can heavily bias rotation-based ages for low-mass K and M dwarfs. We propose to conduct a census of stellar rotation in nearby (d<400 pc) young (<1 Gyr) clusters, moving groups, and stellar streams with the goal of determining when these tight sequences form, and how long stars remain stalled, as a function of mass. We will use FFI data to extract light curves for ~5000 stars distributed across dozens of coeval groups for this purpose.