Testing Model-determined Temperatures in the Hyades: A Bayesian Approach

Abstract

Abstract Gains in our understanding of stellar evolution over the last century are largely due to improvements in stellar models. One key aspect in the use of these models is a reliable transformation between theoretical values (such as luminosity and temperature) to observable quantities (such as magnitude and color). To assess the current state of this transformation, we sought to compare model-determined temperatures from color–magnitude diagram fitting to temperatures obtained from photometric colors or spectroscopy. Our sample for analysis was 88 nonbinary stars in the Hyades open star cluster. By applying a sophisticated Bayesian algorithm we fit five widely available model sets to high-quality photometric data combined with Gaia parallaxes. This analysis provides specific feedback for improving temperature–color transformations, as well as practical guidance for using results based on these models.