A star about the mass of the sun, also called an intermediate-mass star, is born fusing hydrogen into helium. After it goes through its main sequence lifetime, it undergoes a dramatic change, becoming a red giant for a relatively short time. Eventually, the star finishes the red giant phase and collapses into a white dwarf, its final configuration. The Sun, which contains one solar mass of material and emits one solar luminosity unit of light, will have a main sequence lifetime totaling about ten billion years. It will then be a red giant for about one-tenth that amount of time.