zementums

Zementums are a hypothetical class of celestial bodies that have been proposed in some theoretical models of planetary formation. The concept of a zementum is used to describe a very dense, solid planetary core that might form under extreme pressure and temperature conditions. These cores are envisioned to be composed of materials that are typically considered refractory, meaning they have very high melting points.

The idea behind zementums arises from considering the early stages of protoplanetary disk evolution. As dust grains collide and aggregate, they can reach significant sizes. In the very hot inner regions of a protoplanetary disk, closer to the young star, only the most heat-resistant materials would be able to condense and form solid particles. These refractory materials, such as certain metals and metal oxides, could potentially aggregate to form large, dense cores.

If such a core were to grow sufficiently massive, it could then accrete lighter elements like hydrogen and helium, forming a gas giant planet. However, the solid core itself, if it remained isolated or if the accretion of gas was limited, would be referred to as a zementum. The existence of zementums is speculative, and current observational data has not definitively confirmed their presence. Nevertheless, they remain a useful concept for theoretical explorations of planetary system diversity.