Green and Purple Stars, and Pink--such as they would appear to Humans to be--

Do in fact exist, though they are rare. You just have to look for them. Which serious astronomers, who don't like to be bothered with the constraints and peculiarities of human color-vision, are seldom willing to do. When we ask such conscientious professionals for example, please, to lift their attention from Epicycles and the hypothetical profundities of Dark Matter and Black Holes, and to set the search-parameters of one of their dazzlingly many varieties of telescopes to "Binary Stars, Amethyst/Emerald," such as we are all dying to catch a glimpse of, they reply that to focus on so narrow a color spectrum would be a waste of their valuable telescope's time, and would, essentially, provide too little data to make the observation worthwhile. Really, that's what they're saying. And they also say, dismissively of Pink the color, "Pink isn't a color," which is true, but which proves that they don't know how to look for things that humans want to see, and, perhaps, that they have no souls.