ocr: H-R DIAGRAM Hertzsprung-Russel diagram shows the relationship between stars magnitude and surtace temperature. In the diagram the horizontal axis shows the spec- tral class (surface temperature) while the vertical axis shows the absolute magnitude. When stars are placed into the diagram, most of them settle into a narrow belt, which contains all the main sequence stars. Above it are the giants and under it the dwarts. When a sfar is born ouf of the intersfellar matter, it be- comes denser ond hotter. The star moves from top right to the main sequence, where it stays most of its life. Al- ter t ...
