The Power and Puzzles of Stellar Rotation as a Chronometer

by Mr Federica Chiti (University of Hawai'i)

Friday 14 Mar 2025, 10:30 → 11:30 Europe/Stockholm

FC61 (AlbaNova Main Building)

Stellar rotation is a powerful tool for probing stellar evolution and estimating the ages of low-mass stars via gyrochronology. This technique relies on rotation-age relations, which are shaped by the complex interplay of mass loss, stellar magnetic fields, and internal angular momentum transport. Due to uncertainties in these processes, gyrochronology has historically depended on calibrators—systems with known ages and rotation periods—to anchor the degree of angular momentum loss over time. While missions like Kepler and TESS have dramatically increased rotation datasets and identified numerous young open clusters as gyrochronology benchmarks, a critical deficiency persists: the scarcity of well-characterized, old, low-mass calibrators. Furthermore, these large-scale surveys have revealed anomalous rotation features that are increasingly difficult to reconcile with existing, simplified models of stellar rotational evolution. In this talk, I will review these challenges and present our efforts to expand the pool of gyrochronology calibrators by leveraging wide binary systems. I will discuss the insights gained from this study and the current prospects for utilizing rotation as an age diagnostic tool, particularly through the development of advanced models of stellar rotational evolution.