Identifying Uncertainties in Stellar Evolution Models Using the Open Cluster M67

TL;DR

This study compares four stellar evolution model grids using the open cluster M67, revealing systematic differences in age estimates for different star types and recommending specific models for accurate age determination.

Contribution

The paper provides a comparative analysis of four stellar evolution models using M67, highlighting their differences and offering guidance on model selection for age estimation.

Findings

Main sequence star ages are overestimated across models.

Red giant star ages are underestimated across models.

DSEP is recommended for main sequence stars, GARSTEC for red giants.

Abstract

Stellar age estimates are often calculated by interpolating a star's properties in a grid of models. However, different model grids will give different ages for the same star. We used the open cluster M67 to compare four different model grids: DSEP, GARSTEC, MIST, and YREC. Across all model grids, age estimates for main sequence stars were consistently higher than the accepted age of M67, while age estimates for red giant stars were lower. We compared model-generated age and mass values to external constraints as an additional test of the reliability of each model grid. For stars near solar age and metallicity, we recommend using the DSEP model grid to estimate the ages of main sequence stars and the GARSTEC model grid for red giant stars.