Yifeng Mao, Department of Applied Mathematics, University of Colorado Boulder

Chemical transport by waves in stars 

Stellar evolution is governed by the transport and reactions of chemical species. However, we currently lack a comprehensive understanding of how these chemicals migrate within the radiative zones of stars. Previous research has studied the diffusion of chemical gradients due to internal gravity waves (IGWs) excited by the convective cores in the main sequence intermediate- and high-mass stars. Studying the properties of IGWs in stars and planets is essential as they are expected to be involved in many physical processes, including rotation, mixing, and magnetism. Whether IGWs can help transport chemicals in the radiative envelope of those main-sequence stars is a significant question of interest. This work combines asymptotic and numerical calculations within an idealized Boussinesq approximation to understand the passive transport of chemicals by waves in stars. It explores the conditions under which waves can transport chemicals and quantitatively predicts the diffusivity of these waves.