[Image Source: The Dragon’s Gaze Artist Rendering]
When stars, much smaller than our sun, reach the end of their lifespan, they shed their outermost layers and become white dwarfs. The material in a white dwarf no longer undergoes fusion reactions, so the star lacks a source of energy. As a result, it cannot support itself by the heat generated by fusion against gravitational collapse, but is supported only by electron degeneracy pressure, causing it to be extremely dense. It is common for astronomers to observe lighter elements such as helium and hydrogen rising to the surface of white dwarfs.