Comet and asteroid types and orbits, illustration. At upper left is the orbit of Kuiper Belt objects, which can include long-period comets. At upper centre is the orbit of a type of minor planet known as a centaur, which can also boil like a comet at the points in its orbit closest to the Sun. At upper right is the orbit of a short-period comet that passes into the inner solar system. At lower left is a centaur, with ices evaporating as it nears the Sun. At lower right is the remains of a centaur with all its volatile materials evaporated away.