Not sure yet :I
However what's actually important is the planet's main moon, Nausicaa. I could make it as the inhabitants came up with a system to survive despite the lack of sun light and heat.
The inhabitants are actually human colonists.
And I read the link but I slept like 2 hours and I didn't catch much, is it saying they could basically absorb heat or energy from a nearby gas giant?
There can be a thin but existing habitable zone around a gas giant, yes. So if you're sixth planet can be a gas giant, you can certainly have a moon that just happens to be in that narrow life-sustaining zone. Its unstable in the long term (evolutionwise) but for colonists I don't see an issue.