The Jovian planets are all large and have low mean densities, indicating they are composed of lightweight gases such as hydrogen and helium, as well as frozen compounds such as ammonia and methane.

• 木星类行星都有体积大密度小的特征，这表明他们成分构成不仅包括冻结复合物，如氨和甲烷，还包括重量轻的气体，如氢和氦。