Seismic diagnostics of red giants: first comparison with stellar models

TL;DR

This paper analyzes the seismic oscillation data of red giants from space telescopes, compares it with stellar models, and highlights how oscillation properties reveal internal structures and evolutionary stages.

Contribution

It provides the first comparison between observed red giant oscillations and theoretical models, emphasizing dipole modes as key diagnostics for stellar evolution.

Findings

Dipole mode properties diagnose evolutionary stages.

Model predictions match initial KEPLER data.

Frequency diagrams forecasted for future observations.

Abstract

The clear detection with CoRoT and KEPLER of radial and non-radial solar-like oscillations in many red giants paves the way to seismic inferences on the structure of such stars. We present an overview of the properties of the adiabatic frequencies and frequency separations of radial and non-radial oscillation modes for an extended grid of models. We highlight how their detection allows a deeper insight into the internal structure and evolutionary state of red giants. In particular, we find that the properties of dipole modes constitute a promising seismic diagnostic tool of the evolutionary state of red-giant stars. We compare our theoretical predictions with the first 34 days of KEPLER data and predict the frequency diagram expected for red giants in the COROT exofield in the galactic center direction.