When some 14 billion years have passed for a star like our sun, it will become a long period (month to a year long) pulsating variable and its pulses 

become stronger and stronger and eventually it ejects its outer layers in a giant shell of gas, a planetary nebula. It also loses a lot of its mass in a strong solar wind. At the end of the variable stage fusion quits for good. 
 

The remnant of any giant with less than 1.4 solar masses will shrink into a rapidly spinning star corpse about the size of the earth (3-10,000mi), a white dwarf. Typically they mass 0.5-1 solar mass.  Being as small as they are, densities of matter in a dwarf star are enormous, a million times more dense than water (.1-10 tons/cm3).  Matter has been so compressed that its electrons are nearly touching, and the repulsion of the like charges prevents matter from being compressed further. We call this degenerate matter. Even though fusion reactions are no longer taking place in dwarf stars, for a while they will still radiate (glow) from their accumulated heat. Over billions of years, as they cool, they fade and disappear from sight to become black dwarfs.