Planetary Ring System

A planetary ring system is a disc or ring orbiting a astronomical object. Planetary ring systems are mainly composed of dust or small asteroids, typically called moon-lets. Ring systems are commonly found around gas giants, but small ring systems have been found on asteroids and dwarf planets. Ring systems are made from collisions or by smaller planets/moons, hitting it's Roche limit. Ring systems can also be composed in parts, as seen on Saturn.

Moon-lets are thrown out away from the planet, colliding with one another and breaking apart constantly as they orbit. and sunlight should photo-dissociate ring particles. The only thing keeping ring's stable and maintained is gravity.

Orbital resonance can tug at ring particles, keeping them in place. Shepherd moons can fit through the Roche limit and can pull on ring particles, making particles out of place, and create gaps in the rings which create room for moons. Moons that have cryovolcanism can also make there own dim rings.

Formation
As a planet or moon come into the bigger planet's Roche limit, the smaller planet experiences tidal forces, which will overtake the the smaller planet's own gravity, causing it to split into tiny asteroids and dust. These remnants of the smaller planets start orbiting around the bigger planet at very fast speeds, due to the proximity of the bigger planet. However there is another way to get a planetary ring system. These can form when the planets is early in life. When leftover debris are floating around close to the planet, they can start to orbit around the planet that is forming. When rings are formed this way, they are usually farther from the planet.

Classification
Ring systems can come into 3 types, all based on the ring's material. There are rocky rings found near planets relatively close to stars, Metal Rings, which are found on Hot Jupiters which are rich in metal due to the proximity. And Ice rings, the most common type of rings which are found on cold gas giants, like Jupiter, Saturn, Uranus and Neptune.

Worldbuilding in Practice
"There are many moons around Ikanos, a cold gas giant, Ikanos has 2 moons which are frigid and are similar to Enceladus. Ikanos has huge rings, ranging from where Io would be compared to Jupiter. There is supposed to be a Station settled near the planet in the frozen rings it has. The bright A Type star shines over the construction zone, as all of them are frozen to the bone, waiting for a break. Since the rings are huge it is planned to be a mining zone for ice and maybe some minerals. However the view is gorgeous, something to be in awe about."