Modelling the Shear Layer Oscillation and its impact on the rotation of low-mass stars

Abstract

In this work, we study the interaction between the Internal Gravity Waves (IGW) and the mean rotation profile occurring in Sun-like stars just below the convective zone on a thin part of the radiative zone. This interaction takes the shape of an oscillation of the rotation profile over time, the so-called Shear Layer Oscillations (SLO). The understanding of the SLO, which occurs on time scales of the order of the year, is necessary to know whether IGW can explain the disagreement between the observed low core rotation frequency in main sequence and evolved low-mass stars and the current predictions of our theoretical models. Including the effects of the SLO in a stellar evolution code, which deals with time scales of the order of the billion years (lifetime of stars), is a real challenge (due to the huge difference between the time scales of the SLO and stars). This work aims to describe the SLO through simple prescriptions in order to include its effects in such a code.