Abstract The Hertzsprung-Russell diagram (HRD) is a fundamental representation in stellar physics. It contains information about key properties of stars and allows inferences about stellar evolution. The use of the HRD is an important disciplinary activity in astrophysics. For example, it is particularly important to have a graphical understanding of the HRD in order to understand elementary astrophysical relationships (e.g., about the luminosity, temperature, radius, and mass of stars).
