Comparison between the Type-1 and Type-2 planets. Left column: total H₂O equivalent in the interior assuming saturated Mg-silicates in the mantle and hydrogen content in the core computed from Sieverts law. Middle column: partitioning into separate contributions from the mantle- and core reservoirs. Right column: relative effect δR₁ ∕R₁ ≡ (R₂ − R₁)∕R₁ of hydrationon total planetary radius at given mass, composition and surface temperature (see also Fig. 1).