The Universe ________________________________________________________________ 17. Characteristics of stars
Figure 10.29 Hertzsprung-Russell diagram. Brightness: depends on its composition, the amount of energy that the star releases and how far it is from the planet. The closer it is to the Earth, the brighter it looks.
Colour: stars have different colours, which are indicators of temperature. Stars exist in a range of colours: red, orange, yellow, green, white and blue with red being the coolest and blue or blue-white being the hottest.
The Hertzsprung-Russell diagram (on left) is a plot of luminosity (absolute magnitude) against the colour of the stars ranging from the high-temperature blue-white stars on the left side of the diagram to the low temperature red stars on the right side