Ugh...here we go again....
Excuse me if I'm mistaken, but I don't recall ever having had a conversation with you. That being said, it's hard to ignore an invitation such as yours.
First, let me pose a philosophical question: what is green?
Your philosophical belief system is not at issue here. You can believe whatever you wish. I prefer hard science, but you go ahead and discuss your faith as you see fit.
In this case, green is light, the wavelength of which falls roughly between 520nm to 570nm. Its frequency is in the range of 525-575THz.
Our own Sun's peak light emissions fall within the green range, so it can be said to be a green star.
In fact, with the billions of stars within our own galaxy, there are many more stars that emit green light.
Your eyes can't see it, but there is also infrared and ultraviolet light that falls outside of your ability to see. Whether you wish to believe it or not, these colors exist. There has even been a technology around since the late 1950s that can take infrared light and convert it into viewable photographs. Amazing as it may seem, this is real stuff that you can hold in your hands.
In fact, there are many things that you can't see, but they exist. Black holes, X-rays, viruses and ideas among others.
Yes, the Drengin Empire fleet orbiting Earth (which inside a giant bubble of invincibility) demands realism.
LOL! And there's that too.