DuFussMcGoo:THERE ARE NO GREEN STARS !
"Our eyes have light-sensitive
cells in them called rods and cones. Rods are the brightness detectors
and are blind to color. Our eyes have three kinds of cones that help us
see color: red cones, blue cones and green cones. When light hits them,
each gets triggered by a different amount; red light — say, from a
strawberry — really triggers the red cone, but the blue and green cones
stay rather calm.
Most
objects don't emit (or reflect) one color, so the cones are triggered by
varying amounts. An orange, for example, triggers the red cones to go
about twice as much as the green cones but leaves the blue ones alone.
When the brain receives the signal from the three cones, it says, 'This
must be an orange object.' If the green cones see just as much light as
the red, with the blue ones not seeing anything, we interpret that as
yellow. And so on.
So the only way to see a star as green is for it to almost exclusively emit green light.
However, stars are always producing more than one wavelength of light.
Any star emitting mostly green will also be putting out lots of red and
blue, making the star look white. Changing the star's temperature will
make it appear slightly orange, yellow, red or blue, but you just can't
get green. Our eyes simply won't see it that way.
That's why there are no green stars. The colors emitted by stars and how our eyes see them pretty much guarantee it."
https://www.discovermagazine.com/the-sciences/why-are-there-no-green-stars
EDIT: I am confident Joe already knew this and, most likely, actually sees green stars (clovers too).