Back to star system generation. Star mass, derived luminosity, mass budget for planets based on mass and luminosity, then we splat out a list of planets, each of which may have moons. The simplest mechanic for this is a chart of possibilities like what I would have used for a Sci-Fi RPG like Traveller. There is some mechanism in the real where gas giants ‘tack in’ to their star to get hot jupiters and hot neptunes, hot ice and gas giants, where ‘ice’ giants are lower mass ‘mostly gas’ giants which are less hydrogen and helium and more methane, water and ammonia. All of these gas blobs have rocky cores of a few percent to a few tens of percent.

We get gas midgets, too, except we don’t have any in the solar system that we know of. There’s still the possibility that we will find planet nine (sorry Pluto) which was all but ejected from the solar system by Jupiter. The Kuiper Belt Objects, including Pluto, were probably flung out there by Jupiter. I don’t really understand the mechanism for turning those highly elliptical but not hyperbolic orbits into ones which don’t come right back to Jupiter; maybe they return an encounter with old man Jupiter to get dropped into the sun or further drop-kicked outwards? They can have slow long-term encounters, interacting gravitationally with Neptune. I think the main way they get out of these orbits which come back into the riot is by interacting with each other… oh, and impacting, as is what has obviously happened with the double world of Pluto and Charon.

But all I’m concerned with is setting up some potential worlds out to the edge of the star system, which is 40 AU for the solar system and any star of a similar mass to that of Sol. We have a star mass and derived luminosity as well as a metallicity, all in sols. If we make that a clickable ‘button’ we could reset the star system derived from those stats and reset the star in some other way. Separate ‘New Stat’ and ‘New System’ buttons would work better. Anyway, we can set points and have the orbits thus defined hoover up some of the planetary accretion disk and the rest goes into the star of out of the system, based on metallicity. If we presume 1% is the default and randomly move that up and down a little then base the mass budget of the disk based on that and the stars’ mass. We then look at the adjacent portion of the disk and the neighbors and grab a random portion. We can actually make two heaps and re center the orbit based on the mass of each heap and its’ distance. So, in close to the star the heap is effectively zero and the heap just to the outside is some more reasonable amount, then that first planet is a lot further out. The second world is more likely to have two similar heaps to average out… At some point we get gasses, but I just want to get something up tonight!