Two-dimensional models of early-type fast rotating stars: the ESTER project

TL;DR

This paper presents the latest two-dimensional models of early-type fast rotating stars from the ESTER project, exploring differential rotation, meridional circulation, and their implications for stellar evolution and observable features.

Contribution

The paper introduces advanced 2D models of rotating stars that incorporate differential rotation and circulation, providing new insights into stellar structure and evolution.

Findings

Emergence of Stewartson layers along the core's tangent cylinder

Insights into the evolution of intermediate-mass stars at constant angular momentum

Comparisons between models and interferometric observations of gravity darkening

Abstract

In this talk I present the latest results of the ESTER project that has taken up the challenge of building two dimensional (axisymmetric) models of stars rotating at any rotation rate. In particular, I focus on main sequence massive and intermediate mass stars. I show what should be expected in such stars as far as the differential rotation and the associated meridional circulation are concerned, notably the emergence of a Stewartson layer along the tangent cylinder of the core. I also indicate what may be inferred about the evolution of an intermediate-mass star at constant angular momentum and how Be stars may form. I finally give some comparisons between models and observations of the gravity darkening on some nearby fast rotators as it has been derived from interferometric observations. In passing, I also discuss how 2D models can help to recover the fundamental parameters of a star.