You may be asking yourself, if Vesta is such a huge asteroid, then why is it not considered to be a dwarf planet as well. The answer is rules, rules, rules! Vesta was considered too shapely by the IAU to be a true dwarf planet. Dwarf planets are supposed to be round, you see – "ellipsoidal" to use the precise nomenclature. Vesta has a huge crater making her physically unfit and therefore is designated as one of many thousands of other minor planets even though Vesta is the second-largest asteroid after Ceres.