The effect of different opacity data and chemical element mixture on the Petersen diagram

TL;DR

This study investigates how different opacity data and chemical element mixtures influence the Petersen diagram, which is used to determine stellar parameters like metallicity in pulsating stars.

Contribution

It demonstrates the sensitivity of the period ratio to opacity data and heavy element abundances, providing a method to test opacity models using observations.

Findings

Period ratio is sensitive to opacity data (OPAL vs. OP)

Heavy element mixture affects the period ratio

Comparison with observations can test opacity models

Abstract

The Petersen diagram is a frequently used tool to constrain model parameters such as metallicity of radial double-mode pulsators. In this diagram the period ratio of the radial first overtone to the fundamental mode, P_1/P_0, is plotted against the period of the fundamental mode. The period ratio is sensitive to the chemical composition as well as to the rotational velocity of a star. In the present study we compute stellar pulsation models to demonstrate the sensitivity of the radial period ratio to the opacity data (OPAL and OP tables) and we also examine the effect of different relative abundances of heavy elements. We conclude that the comparison with observed period ratios could be used successfully to test the opacity data.