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Why is Vesta considered a protoplanet?

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Illustration showing a massive asteroid above a city map with a dinosaur silhouette for scale, highlighting the asteroid's size compared to major urban areas. — Asteroid This rock would take out more than just a *T. rex*.

Vesta is classified as a protoplanet rather than a typical asteroid because it possesses a complex internal structure, including an iron core measuring between 214 and 226 km across.12

Unlike a simple "giant rock," Vesta represents a body that would have continued to grow into a full-sized planet had the process of accretion not been interrupted during the early history of the solar system. Its status as a differentiated body is further supported by its role as the parent body for a specific group of meteorites known as basaltic achondrite HEDs (howardite, eucrite, and diogenite).12