Green metallic

As we're considering the sort of star as has a truly habitable zone, we're being asked to look at stellar metallicity [UPDATE 8/8 also Cowing - and on a reread, I had to rewrite this poast].

The issue is ultraviolet. This is all photonic. We're past the M class of stars and are assuming a magnetic-field on the planet. So we are not considering flares of charged-particles. And we're assuming the plants here are green no longer purple.

High-metal stars, which is most of those with planets (albeit mostly the Hot Jupiters), do UV-B (315-400 nm). The Max Planck Institutes in Germany are saying this does ultraviolence, to the Ozone. So we want stars delivering more to the UV-C (100-280 nm). That's metal-poor stars; UPDATE 8/8 we'll deal with hotter stars later.

Although I do wish to know if the thickness of the atmosphere might help offset the UV-B photons. A thickly layered superEarth should bear more Ozone and maybe more volume of the O₃, without poisoning Heavy Los Angeles.

Oh, and those K stars' planets. If they even get greens at all, and if their greenhouse is controlled; they'd better pray the K is low-metallic or else those plants aren't ever spreading outside the oceans.