The effects of individual metal contents on isochrones for C, N, O, Na, Mg, Al, Si, and Fe

TL;DR

This study investigates how individual metal element variations affect stellar isochrone shapes, revealing specific element influences on stellar evolution at different metallicities.

Contribution

It provides a comprehensive analysis of the effects of individual metal contents on isochrones, highlighting the roles of Na, Mg, Al, Si, and Fe in stellar models.

Findings

Na, Mg, and Al influence stellar models similarly.

In high-metallicity conditions, Si and Fe have reduced effects on the red giant branch.

Fe significantly impacts the main sequence compared to other elements.

Abstract

The individual characteristics of C, N, O, Na, Mg, Al, Si, and Fe on isochrones have been investigated in this study. Stellar models have been constructed for various mixtures in which the content of each element is changed up to the extreme value reported in recent studies, and the changes in isochrone shape have been analyzed for the various mixtures. To express the abundance variation of different elements with a single parameter, we have focused on the relative changes in the total number of metal ions. A review of the shape changes revealed that Na, Mg, and Al work the same way in stellar models, as the well-known fact that C, N, and O have the same reactions in the stellar interior. In addition, it was found that in high-metallicity conditions the influence of Si and Fe on the red giant branch becomes smaller than that of Na, Mg, and Al closer to the tip. Furthermore, the influence of Fe on the main sequence is larger than that of Na, Mg, Al, and even Si.