The mic-mac connection inside stars: the interdependence of atomic diffusion and hydrodynamic instabilities

TL;DR

This paper explores how microscopic atomic diffusion and macroscopic hydrodynamic instabilities inside stars are interconnected, affecting stellar structure and evolution, with recent observations highlighting their complex interplay.

Contribution

It investigates the interdependence of atomic diffusion and hydrodynamic instabilities in stars, emphasizing their combined impact on stellar structure and recent observational insights.

Findings

Atomic diffusion can significantly influence stellar internal structure.

Macroscopic motions and microscopic processes are deeply interconnected.

Recent data supports the importance of these interactions in stellar evolution.

Abstract

The interdependence of microscopic (atomic) and macroscopic (hydrodynamic) processes inside stars and their consequences for stellar structure and evolution were recognized by Jean-Paul Zahn several decades ago. He was a pioneer in that respect, discussing the importance of the macroscopic motions related to stellar rotation, in competition with the chemical stratification induced by gravitational settling and radiative accelerations. This has been much developed in recent years, in connection with the improvement of observational data, including asteroseismology. Morover, it has been recently discovered that the microscopic atomic diffusion processes can lead to macroscopic results which may infuence in a non negligible way the internal stellar structure, independently of the abundances observed at the surface.