First Green Star Adds to Milky Way's Rainbow

Astronomers say there's a rainbow of stars above your head, even if you can't see them. A team led by the University of Warwick reports that a white dwarf called WD J1330+6435, about 326 light-years away, appears to be the first credibly identified green star, which team lead Mark Hollands admits to Space.com seems "like something out of science fiction." But Hollands' study, published in RAS Techniques and Instruments, suggests that other "rule-breaking" white dwarfs might appear pink, purple, cyan, and yellow up close, even if such oddballs are rare—roughly 1 in 30.

Named for their typical glowing white or pale blue hue, white dwarfs may only appear white because they are so far from Earth, the team suggests, finding evidence that their dense helium atmospheres can take on color depending on the elements pulled in. Pink or purple would indicate lots of carbon, cyan or pale blue would suggest a combination of hydrogen and helium, while yellow would point to debris from asteroids, comets, and old planets. With this particular white dwarf, rocky debris from a nearby planet is believed to have supplied sodium that strips out the orange light and leaves a green glow, per a release. The study also flags a second standout: WD J1011+2845, which may be the deepest red-hued star known; Hollands describes it as "almost like a salmon pink," per CNN.