A class F6IV star, Ariel has 14 planets around it, but many of them are barely more than asteroids.  Much of the rest of the system is covered in asteroids.  Some speculate that this is simply a system that never matured into a full solar system with planets.  Most are hit by asteroids on a regular basis.  These cling to them, making the planets larger; all except one,  Julian, which houses many pirates and others who don't want to live under another's rule.
​Julian has an atmosphere strong enough to destroy the constantly bombarding asteroids.  Its a thick sort of air, and only the hearty can breathe it, but one needs to be hearty in any case to be on this planet, for little law exists here except what one can gain at the end of their gun.  Pirates and other criminals usually live here, and almost no "decent folk."