Transformations from theoretical Hertzsprung-Russell diagrams to color-magnitude diagrams: Effective temperatures, B-V colors, and bolometric corrections

This paper provides improved numerical relations between effective temperatures of stars, their B-V colors, and their bolometric corrections (BCs) for the purpose of comparing theoretical stellar evolutionary calculations to color-magnitude diagrams of star clusters. Temperatures and bolometric correction measurements for 335 stars from the literature form the observational basis for the transformations. Measured temperatures range from 2900 to 52,500 K. Polynomial fits to the observations give relations between effective temperatures and B-V colors and between temperatures and bolometric corrections. Hot supergiants appear to have a T-eff:B-V relation slightly different from those of main-sequence stars, subgiants, and giants. All luminosity classes appear to follow a unique T-eff:BC relation. The T-eff:BC relation for stars with temperatures less than similar to 5000 K, however, is uncertain because temperatures of the coolest stars are determined from uncertain angular diameters.