Astronomers discover the first green star, a white dwarf glowing greenish-yellow

Astronomers analyzing white dwarfs near Earth have identified the first star that would appear green to human eyes, based on spectral data in a new study.

• Hollands said normal stars can only appear orange, white or blue, while unusual physics in some white dwarfs' outer layers causes larger color deviations.
• The greenish-yellow glow arises because dense helium makes sodium atoms absorb a broadened range of yellow, orange and red wavelengths, Hollands said.
• Hollands said calcium, sodium and lithium on the star's surface were deposited by rocky planetary debris that was shredded and accreted onto the white dwarf.
• The study, published in RAS Techniques and Instruments, analyzed 151 known white dwarfs located within 20 parsecs of Earth.