White dwarfs are common across the universe. Despite their diminutive size, white dwarfs are still extremely dense. For example, the white dwarf located 130 light-years away called WD 0525+526 is 20 percent larger than our sun—so large that astronomers classify it as an “ultra-massive” white dwarf. What’s left behind is a massive white dwarf with a hydrogen-helium layer that’s 10 billion times thinner than usual, allowing detectable carbon to reach the surface. But a major reason why experts have difficulty finding binary star white dwarfs is because of their trademark ultraviolet emissions.