Radiative Accelerations in Stellar Evolution

TL;DR

This paper reviews methods for calculating radiative accelerations in stellar evolution, discusses their limitations, and applies them to different star populations, showing atomic diffusion models can explain observed abundance anomalies without overshooting.

Contribution

It introduces improved models of radiative accelerations in stellar evolution, demonstrating their role in explaining abundance anomalies and core boundary criteria without overshooting.

Findings

Models including atomic diffusion satisfy Schwarzschild's criterion on the HB.

Radiative accelerations lead to abundance anomalies similar to observations.

Atomic diffusion models can explain HB star properties without overshooting.

Abstract

A brief review of various methods to calculate radiative accelerations for stellar evolution and an analysis of their limitations are followed by applications to Pop I and Pop II stars. Recent applications to Horizontal Branch (HB) star evolution are also described. It is shown that models including atomic diffusion satisfy Schwarzschild's criterion on the interior side of the core boundary on the HB without the introduction of overshooting. Using stellar evolution models starting on the Main Sequence and calculated throughout evolution with atomic diffusion, radiative accelerations are shown to lead to abundance anomalies similar to those observed on the HB of M15.