Astronomers find the first star that would look green

Stars were supposed to come in a short list of colors — red, orange, white, blue — and green was never on it. Astronomers at the University of Warwick have now found a star that would genuinely look green up close: a white dwarf, the dense, Earth-sized ember left behind when a sun-like star burns out. Rocky material rich in sodium has drifted into its atmosphere, and that sodium soaks up yellow, orange and red light, leaving a ghostly green behind. In a wider survey published in the journal RAS Techniques and Instruments, the team shows other white dwarfs can shade pink, purple, cyan or yellow, depending on what they are made of — a whole hidden rainbow in the oldest stars in the sky.