The Universe

i.Explain how stars can be classified according to size, colour and temperature.
Astronomers use The Hertzsprung-Russell Diagram, which is a graphical tool to classify stars according to their luminosity, spectral type, color, temperature and evolutionary stage. In this diagram, the brightest stars lie near the top of the diagram and the hottest stars lie to the left. On the H-R diagram, most of the stars, including the Sun, fall along a diagonal line that goes from the upper left to the lower right of the diagram. …