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

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.

arXiv commentpublished in ApJ (Aug 1. 2016) / accepted for publication in ApJ (May 25. 2016) / 11 pages, 9 figures, 5 tables / ads address: http://adsabs.harvard.edu/abs/2016ApJ...826..155B

References in corpus (19)

• The chemical composition of the Sun
• Low Temperature Opacities
• Towards Better Age Estimates for Stellar Populations: The Y^2 Isochrones for Solar Mixture
• Na-O Anticorrelation and HB. VII. The chemical composition of first and second-generation stars in 15 globular clusters from GIRAFFE spectra
• Na-O Anticorrelation and HB. VIII. Proton-capture elements and metallicities in 17 globular clusters from UVES spectra
• Element Diffusion in the Solar Interior
• The O-Na and Mg-Al Anticorrelations in Turn-Off and early Subgiants in Globular Clusters
• The Ages of 55 Globular Clusters as Determined Using an Improved delta V_TO^HB Method Along with Color-Magnitude Diagram Constraints, and Their Implications for Broader Issues
• The YY Isochrones for alpha-element Enhanced Mixtures
• The double Subgiant Branch of NGC 1851: the role of the CNO abundance
• Abundances of C, N, O in slightly evolved stars in the globular clusters NGC 6397, NGC 6752 and 47 Tuc
• A large stellar evolution database for population synthesis studies. V. Stellar models and isochrones with CNONa abundance anticorrelations
• Stellar Models with Enhanced Abundances of C, N, O, Ne, Na, Mg, Si, S, Ca, and Ti, in Turn, at Constant Helium and Iron Abundances
• Stellar Population Models and Individual Element Abundances I: Sensitivity of Stellar Evolution Models
• The C+N+O abundances and the splitting of the subgiant branch in the Globular Cluster NGC 1851
• C and N Abundances in Stars At the Base of the Red Giant Branch in M15
• On the primordial scenario for abundance variations within globular clusters. The isochrone test
• Photometric properties of stellar populations in Galactic globular clusters: the role of the Mg-Al anticorrelation
• Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way

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• Models of Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. I. Bolometric Corrections Derived from New MARCS Synthetic Spectra and Their Implications for Observed Colour-Magnitude Diagrams
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