This is a general list of how asteroids should look like, depending on the average temperature they face. This list is valuable for bodies too small to hold a tenuous atmosphere.
Oort Cloud Asteroids
Main article: Oort Cloud Asteroid Paraterraforming.
The cold bodies inside the Oort Cloud have different chemistry and physical properties then the asteroids inside the Kuiper Belt.
Interstellar asteroids should behave much like the Oort Cloud asteroids. Temperature and luminosity conditions should not be much different.
Kuiper Belt Asteroids
Main article: Kuiper Belt Asteroid Terraforming.
Between Uranus and Neptune, asteroids can contain solid water, together with other ices (carbon dioxide).
Main article: Centaur Paraterraforming.
Between Jupiter and Saturn, icy asteroids (also known as Centaurs) are safe. It is too cold for water to sublimate, but still too warm for other gasses to stay solid (like nitrogen or carbon dioxide).
Rocky asteroids with ice
Main article: Rocky Asteroid With Ice Paraterraforming.
They are found along the asteroid zone. Ice is kept under surface. The new findings of Dawn spacecraft shows that both Ceres and Vesta have water beneath their crust.
Main article: Rocky Asteroid Paraterraforming.
Main article: Vulcanoid Paraterraforming.
If a hot celestial body stays closer then the orbit of Mercury, it must lack of some elements that become volatile, like lead. They are also known as Vulcanoids. Paraterraforming is possible for them, as described in Vulcanoid Paraterraforming.
Hot endangered asteroids
When temperature exceeds 1500 K, solids start to sublimate and are fast removed by the solar wind.
Special kind of objects
- Comets are celestial bodies moving on an elliptical orbit. They were once part of the Kuiper Belt or the Oort Cloud, but because of various perturbations, their orbit now brings them very close to the Sun.
- Rings are found around the four gas giants and are composed of millions of tiny satellites. Some M - type stars, White dwarfs and Brown Dwarfs might have their own rings, at least in theory.
If an asteroid from a category moves closer, it will become a comet. If it moves further, its life is not endangered.
Asteroids are too small for terraforming, but are good candidates for Paraterraforming. Future cities can be created on the surface or underground, where they can create huge caverns.