The interior of the dwarf planet Ceres is structurally weak, consisting distinct layers at different depths, with the densest layer at the core, a study based on data from NASA’s Dawn spacecraft suggests.
Water and other light materials partially separated from rock during a heating phase early in Ceres’ history, said Ryan Park, the study’s lead author from NASA’s Jet Propulsion Laboratory says.
Ceres is much less dense than Earth, the moon, giant asteroid Vesta – Dawn’s previous target – and other rocky bodies in our solar system.
“We have found that the divisions between different layers are less pronounced inside Ceres than the moon and other planets in our solar system,” Park says.
“Earth, with its metallic core, semi-fluid mantle and outer crust, has a more clearly defined structure than Ceres.”
The study relied on data about Ceres’ own motion to draw conclusions about its inner structure. The scientists measured variations in Ceres’ gravity by tracking subtle changes in the motion of the spacecraft.
The study gives some hints about the internal processes that could have occurred during the early history of Ceres.
“We know from previous Dawn studies that there must have been interactions between water and rock inside Ceres,” said Carol Raymond, a co-author.
“That, combined with the new density structure, tells us that Ceres experienced a complex thermal history.”