Why aren’t there any green stars?
There are no green stars because the ‘black-body spectrum’ of stars, which describes the amount of light at each wavelength and depends on temperature, doesn’t produce the same spectrum of colours as, for example, a rainbow. A star whose peak light emission is at a wavelength we might call ‘green’ actually produces almost as much red light, and our eyes interpret this combination as white, not green. For our eyes to see it as green, a star would have to emit only green light, which is not possible.
Source