[Space] Various Star System Generation Thoughts and Questions

[Agemegos]

Originally Posted by Nemoricus

2. The third star of a trinary system must orbit at a distance greater than that of the second star, but no hard rules are given for how much greater.

It is the +6 modifier on the roll for orbital separation for second companions that is supposed to handle this.

The maximum separation of a subcompanion must be no more than one-third its closest approach to any other star. If it exceeds that, its maximum separation is multiplied by 1/3.1 and its other orbital parameters adjusted accordingly, for the same reasons as in 2.

It is the -6 modifier to the roll for orbital separation of sub-companions that is supposed to handle this.

From the tables on page 105, the closest one star may approach its primary is 0.04 AU, and so I think that it would be appropriate to boost the minimum separation of a star to this value

It would better reflect the physical processes involved to remove the companion and add its mass* to the primary. There is no effect in Nature that moves companion stars outwards as their primaries swell.

(* Caution! An astronomer might come along and tell you that something more violent would in fact occur.)

2. The luminosity based inner limit can be inside the star for cool giant stars, specifically for giant stars cooler than about 3950 K. This can result in a planetary orbit being placed inside the star, especially if it is an epistellar gas giant. Contrary to my general inclination to preserve objects when possible, in this case I think it most convenient to declare that the planet is destroyed.

Indeed. Even if the outer parts of the red giant aren't actually hot enough to evaporate silicates such as enstatite drag from the stellar material will cause the planet to lose orbital speed and it will spiral in to the centre of the red giant.

In particular, what should be done if the snow line exists between the limits of the zone or if it exists inside of the zone's inner limit?

Start placing orbits just inside the outer limit and work your way inwards? That's how I read the fifthe paragraph of Step 22 (p.108).