Gas giant
The smallest known extrasolar planet that is likely a "gas planet" is Kepler-138d, which has the same mass as Earth but is 60% larger and therefore has a density that indicates a thick gas envelope.
List of minor planets
The vast majority of minor planets are evenly distributed between the inner-, central and outer parts of the asteroid belt, which are separated by the two Kirkwood gaps at 2.5 and 2.82 AU. Nearly 97.5% of all minor planets are main-belt asteroids (MBA), while Jupiter trojans, Mars-crossing and near-Earth asteroids each account for less than 1% of the overall population. Only a small number of distant minor planets, that is the centaurs and trans-Neptunian objects, have been numbered so far. In the partial lists, table column "category" further refines this principal grouping: