Fig8_5 Giants, Supergiants and white dwarfs

Fig8_5 Giants, Supergiants and white dwarfs

Fig. 8.5 . The vast majority of stars occupy the main sequence in the H-R diagram. Stars with a mass comparable to that of the Sun will evolve into helium-burning giant stars, illustrated by Aldebaran and Arcturus in this diagram. These red giants are a bit cooler than the Sun, but about 100 times more luminous. The luminosity (left vertical axis) is in units of the Sunís luminosity, denoted L?. More massive stars, which have shorter lifetimes on the main sequence, evolve into supergiant stars that are between 10,000 and 1,000,000 times as luminous as the Sun. Antares and Betelgeuse illustrate the supergiant stars on this diagram. After depleting all their helium fuel, the less-luminous giant stars evolve into white dwarf stars of very low luminosity and initially hot disk temperatures. They are illustrated in the bottom left of this diagram by Sirius B, 40 Eridani B and Procyon B.

Copyright 2010, Professor Kenneth R. Lang, Tufts University