In the graph, each circle represents an individual star. The position of the circle’s center indicates the star’s temperature in kelvins (K) and its luminosity (rate of energy emission) relative to that of the sun (Lsun). Note that higher temperatures are to the left. The size of the circle indicates the relative physical size of the star, and the labels indicate the types of stars shown. Apart from the main sequence stars, the group of stars with the greatest range of temperatures is the group of: - Red giants - Red supergiants - White dwarfs - Blue giants