White light contains all the visible-light colors smeared together. The human eye detects green, but green is in the middle of the visible-light spectrum. Your eyes see white when looking at a star emitting its peak radiation in the green part of the visible-light spectrum. &MDASH; Laura Layton, Associate Editor
Green stars do exist. A star’s color indicates its temperature. Green stars emit radiation most intensely at wavelengths in the green part of the visible-light spectrum. They also emit radiation over the range of visible-light wavelengths.