Which type of stellar remnant is composed mostly of electron-degenerate matter?

A white dwarf is composed primarily of electron-degenerate matter, which results from the core of a star that has exhausted its nuclear fuel and shed its outer layers. In the stellar evolution process, when a star like our Sun reaches the end of its life cycle, it expels its outer envelope, leaving behind a hot, dense core. This core is crushed under gravity to the point where electrons are forced into a state called electron degeneracy. In this state, the electrons occupy the lowest energy states available, and the pressure they exert is what prevents further gravitational collapse, despite the absence of nuclear fusion.

The other types of remnants, such as red dwarfs and red giants, refer to stages in stellar evolution rather than end states, and a white giant is not a recognized term in the context of stellar endings. Therefore, they do not pertain to the composition associated with electron degeneracy like white dwarfs do.