the.com/white dwarf

means A white dwarf is the small, dense, slowly cooling core left behind after a star like our Sun burns through its fuel and sheds its outer layers.

from The name is descriptive, not mythic: 'white' for the hot white-hot glow these stellar remnants give off, and 'dwarf' for their startlingly small size compared to ordinary stars — Earth-sized, despite packing roughly a sun's worth of mass. The first one identified, a faint companion star in the Sirius system, puzzled astronomers in the early 20th century once they worked out it was both scorching hot and tiny, a combination that didn't fit any star they knew. The term 'white dwarf' took hold as astronomers in the 1910s–20s classified stars by color and size, settling into use as the physics of these collapsed cores — electron degeneracy pressure holding them up against gravity — was worked out in the following decades.