A graph that shows the relationship of a star's temperature to its absolute magnitude is called HERTZSPRUNG - RUSSEL DIAGRAM.
Hertzsprung Russel diagram is a scatter plot that is typically used to show the relationship between star absolute magnitude and their effective temperatures. The absolute magnitude of a star refers to how a bright a star will appear if it is located 32.6 light years from the earth.
Astronomers use Hertzsprung Russel diagram to classify stars into different classes based on their colour, spectral, temperature and evolutionary stage.
