Physical Sciences and Mathematics Commons^™

From Canonical To Enhanced Extra Mixing In Low‐Mass Red Giants: Tidally Locked Binaries, Pavel A. Denissenkov, Brian Chaboyer, Ke Li

Dartmouth Scholarship

Stellar models that incorporate simple diffusion or shear-induced mixing are used to describe canonical extra mixing in low-mass red giants of low and solar metallicity. These models are able to simultaneously explain the observed Li and CN abundance changes along the upper red giant branch (RGB) in field low-metallicity stars and match photometry, rotation, and ¹²C/¹³C ratios for stars in the old open cluster M67. The shear mixing model requires that main-sequence (MS) progenitors of upper RGB stars possessed rapidly rotating radiative cores and that specific angular momentum was conserved in each of their mass shells during …