Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physical Sciences and Mathematics
From Canonical To Enhanced Extra Mixing In Low‐Mass Red Giants: Tidally Locked Binaries, Pavel A. Denissenkov, Brian Chaboyer, Ke Li
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 …
Theoretical Uncertainties In Red Giant Branch Evolution: The Red Giant Branch Bump, Stephan R. R. Bjork, Brian Chaboyer
Theoretical Uncertainties In Red Giant Branch Evolution: The Red Giant Branch Bump, Stephan R. R. Bjork, Brian Chaboyer
Dartmouth Scholarship
A Monte Carlo simulation exploring uncertainties in standard stellar evolution theory on the red giant branch of metal-poor globular clusters has been conducted. Confidence limits are derived on the absolute V-band magnitude of the bump in the red giant branch luminosity function (MV,b) and the excess number of stars in the bump, Rb. The analysis takes into account uncertainties in the primordial helium abundance, abundance of α-capture elements, radiative and conductive opacities, nuclear reaction rates, neutrino energy losses, the treatments of diffusion and convection, the surface boundary conditions, and color transformations. The uncertainty in …