Terraforming Planets to allow colonization

If you are playing Twilight of the Arnor, then some of the uninhabitable planets can be colonized by researching the right technology. (For example, a "radioactive" planet can be colonized if you have radioactive colonization--refer to the tech tree for the correct terminology--I'm paraphrasing here). These planets have small red icons around them that turn yellow with the first colonization tech and then green with the advanced colonization tech. Some planets are simply uninhabitable. These planets have no icons. 

Yeah I knew about the new planet types. I was asking about the uninhabitable ones. Would have been nice.

Thanks for responding.

No not that I know of, Class 0 planets can not be Colonized at all, or at least what I know of. 

"These planets have small red icons around them that turn yellow with the first colonization tech and then green with the advanced colonization tech."

What is the difference between a planet being yellow or green in this situation?  I've been scouring the web and can't find the answer.  Basically, what is the difference between Aquatic Colonization and Advanced Aquatic Colonization?

Yellow gives you 50% cuts to production, research, economic activity, probably influence and morale as well.

Thanks, that's what I was missing.

It would probably be simpler to remove the ability of the game to mark 'any' world at 0 pq.  And increase the Barren Worlds percentage.    I don't know where this file is, but it should b easy to find, as it is different in TA than the other versions.

Colonization techs only affect production-not research, tax income, etc.

In theory, that would be simple, but I've looked around quite a bit in the game's data files and I've never seen it-I'm fairly positive it's hardcoded.  TA 2.x does introduce sliders for the frequency of extreme planets, but that's hardly the same thing as directly editing the quantity of each type...