In "The Search", the founder homeworld is described as a "rogue planet", one without a solar system.
It is also referred to as a Class M planet... and indeed, Humans, a Bajoran, a Trill and a Romulan are shown to be able to survive on it with no adverse effect.
How does that work out? How does a planet support Human life without being in a solar system's goldilocks zone?
It's a relatively minor plot point in the end, but it is somewhat intriguiging, hence my quandary.
Just thought of a possible explanation: planetwide artificial life support put in place by the founders to allow survival of Vorta and non-sentient life.
Bit weak/hair-pulled, though.