System Builder
System Age
The first step is to determine, broadly, how old your star system is. The following table has a bias toward creating an "established" solar system outside of the Archaean and Hadean period of planet formation. However, it is possible. Different eons of planetary formation will also impact whether life has had a chance to develop on the planet. The longer the system has existed in the Main Sequence, the better chances life has for gaining a foothold.
System Age Table
| 1d100 | SYSTEM AGE | MODIFIERS |
|---|---|---|
| 01-04 | 2d10x10 Million Years | BIO set to 0 |
| 05-15 | 1d10x100 Million Years | BIO -40 |
| 16-20 | 1d4-1 Billion Years (minimum 1 Billion) | BIO -10 |
| 21-45 | 1d6 Billion Years | |
| 46-70 | 1d10 Billion Years | |
| 71-85 | 2d6 Billion Years | |
| 86-94 | 2+2d6 Billion Years¹ | BIO +10 |
| 95-00 | 3+2d6 Billion Years¹ | BIO +15 |
System Age Notes
¹ This could theoretically create a star system believed to have existed before the Big Bang Primordial Singularity (which was somewhere between 13.8 and 14.6 billion years ago). Science should have a fun time trying to explain that one!
Creating Stars
At the heart of your solar system will be at least one star (or perhaps, a post-star). This engine does more to influence the makeup of the system than any other piece.
Large, hot stars usually burn through their fuel and explode before a planetary system forms and may blow all the material components for making planets into the outer system or even out of the system altogether. On the opposite end, small, cool stars may last for a long time, but they lack sufficient gravity to on to much material (or planets) in the outer system. Large planets tend to escape from them.
Stars also vary in size, even in the main sequence (the period when a star is considered most stable).