4 Vesta
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Vesta is one of the largest objects in the asteroid belt, with a mean diameter of 525 kilometres (326 mi). It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta, the virgin goddess of home and hearth from Roman mythology.
True color image of Vesta taken by Dawn. The massive Rheasilvia Crater dominates Vesta's south pole.
Vesta, Ceres, and the Moon with sizes shown to scale
SPHERE image is shown on the left, with a synthetic view derived from Dawn images shown on the right for comparison.
Claudia crater (indicated by the arrow at the bottom of the closeup image at right) defines the prime meridian in the Dawn/NASA coordinate system.
Protoplanet
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A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other's orbits and collide, gradually coalescing into the dominant planets.
A surviving protoplanet, Vesta