Red Giant Oscillations: Stellar Models and Mode Frequency Calculations

TL;DR

This paper models a metal-poor red giant star observed by Kepler, comparing theoretical oscillation frequencies with observed data to understand stellar properties and uncertainties.

Contribution

It provides a detailed comparison of theoretical models and Kepler observations for a metal-poor red giant, highlighting uncertainties in stellar parameters.

Findings

No preferred model within computed mass range.

Uncertainty of about 30 K in T_eff.

Uncertainty of 2.5 Gyr in age.

Abstract

We present preliminary results on modelling KIC 7693833, the so far most metal-poor red-giant star observed by {\it Kepler}. From time series spanning several months, global oscillation parameters and individual frequencies were obtained and compared to theoretical calculations. Evolution models are calculated taking into account spectroscopic and asteroseismic constraints. The oscillation frequencies of the models were computed and compared to the {\it Kepler} data. In the range of mass computed, there is no preferred model, giving an uncertainty of about 30 K in $T_eff$, 0.02 dex in $\log g$, $0.7 \,R_\odot$ in radius and of about 2.5 Gyr in age.