Physical processes leading to surface inhomogeneities: The case of rotation

Abstract

In this lecture I discuss the bulk surface heterogeneity of rotating stars, namely gravity darkening. I especially detail the derivation of the !-model of Espinosa Lara and Rieutord (Astron Astrophys 533:A43, 2011), which gives the gravity darkening in early-type stars. I also discuss the problem of deriving gravity darkening in stars owning a convective envelope and in those that are members of a binary system.