= Protoplanet
A <protoplanet> is a growing planetary body within a planet-forming system. It has accumulated enough <mass> for gravity to strongly influence subsequent collisions and accretion, while its final orbit, composition and <mass> may still change substantially.
Accreting a small <mass> $\Delta m$ onto a body of <mass> $M$ and radius $R$ can release <energy> of order $GM\Delta m/R$. Heating, melting and chemical differentiation can therefore accompany growth. A protoplanet may continue to accumulate, merge with another body, lose material or be scattered; the name describes a stage of evolution rather than guaranteeing a particular final planet.
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