Rotational Stalling Ends when Main-sequence Core Temperatures are at a Minimum

Abstract

Low-mass stars spin-down over time due to angular momentum loss from magnetized stellar winds. This spin-down is interrupted by an epoch of stalling where stars halt their spin-down for 0.1–2 Gyr. Duration of the stalling epoch is mass-dependent, with higher mass stars spending less time stalled than the lowest mass stars. We demonstrate that the mass-dependent age at which stars resume spinning down correlates with the age where low-mass stars are predicted to achieve their minimum core temperature on the main sequence. This suggests that the stalling epoch is commensurate with a phase in low-mass main-sequence star evolution where stars develop a small convective core and their convective envelopes are growing in mass.