Astronomers have directly measured the mass of a single, isolated white dwarf — the surviving core of a burned-out, Sun-like star. Researchers found that the white dwarf is 56 percent the mass of our Sun. This agrees with earlier theoretical predictions of the white dwarf’s mass and corroborates current theories of how white dwarfs evolve as the end product of a typical star’s evolution. The unique observation yields insights into theories of the structure and composition of white dwarfs.