Study identifies a white dwarf that would appear green

Astronomers have identified the first known white dwarf that would appear green to human eyes, using measurements of starlight and a model of human vision rather than direct observation. The finding, reported in a study published in RAS Techniques and Instruments, adds to evidence that these stellar remnants can appear in a wider range of colors than their name suggests. The object, designated WD J13306435, is a dense remnant of a star. Researchers inferred its color by processing its spectrum, which records how its light varies across wavelengths, through a model of how people perceive color. The green appearance is therefore calculated from the star’s light, not a color astronomers saw with the naked eye. The study examined spectra from 151 white dwarfs within about 65 light-years of Earth. Five showed unusual colors, which the researchers described as roughly one in 30 in the sample. The study also found that the average white dwarf in a representative population remains white. White dwarfs form when stars like the Sun reach the end of their lives and leave behind dense remnants. For most stars, color is largely determined by temperature. But the study suggests that the...