Then there are moons of Gas Giants within habitable zones, which can have orbits of 2 mln kilometres, ie, within a several weeks they move 4 mln kilometres closer to the star, than back, not including ecliptical orbit of the giant itself.
Well. 2Mkm is peanuts at this scale you know...
Earth have a 5Mkm difference between its aphelion & perihelion.
And a Jovian sized object in place of the earth would have a hill sphere radius of 3Mkm. Even an object 5 time more massive will still only have a 6Mkm radius. Good ol' sun is quite massive.
Too bad Aurora generated system does not seems to take this constraint into account, leading to some quite funny results
More into the subject : I'm in favor of keeping it moderately simple, but adding a need for water to the mix would be welcome.
Also, the sudden "Cost 2 to 0 thanks for the 0. 0999 atm of oxygen becoming 0. 1 atm is quite annoying.
[edited : I'm still a noob as it seems...]
"An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere." Thanks Wikipedia