New Research Indicates Vesta Lacks a Metal Core

A recent analysis of data from NASA’s Dawn Spacecraft indicates that Vesta, the second-largest asteroid in our solar system, has not fully differentiated into a metallic core, silicate mantle, or basaltic crust.

First discovered by Heinrich Wilhelm Olbers on March 29, 1807, Vesta is the only significant asteroid visible to the naked eye.

It completes a rotation in 5.34 hours, orbits the Sun in 3.63 years, and has an elongated shape with dimensions of 286 x 279 x 223 km.

Due to its substantial size, Vesta is regarded as a differentiated body with a core and mantle, similar to our own planet.

“There has been significant effort put into this research,” noted Dr. Seth Jacobson, a researcher from Michigan State University, along with his colleagues.

“One possibility is that Vesta has undergone incomplete differentiation, meaning it initiated the necessary melting process to create distinct layers such as a core, mantle, and crust, but never completed it.”

“Another theory suggests that Vesta is a fragment of a larger body that contributed to the formation of planets in the solar system.”

“The Jet Propulsion Laboratory has played a crucial role in this research,” explained Dr. Ryan Park, a senior research scientist and principal engineer at NASA’s Jet Propulsion Laboratory.

“After nearly ten years of advancements in calibration and processing technology, we have achieved remarkable consistency between the Dawn spacecraft’s Deep Space Network data and its onboard imaging data.”

“We were eager to see the strength of the data in revealing Vesta’s deep interior.”

“Our findings suggest that Vesta’s history is far more complex than previously thought, influenced by unique processes such as interrupted planetary differentiation and late-stage collisions.”

Celestial bodies with dense cores behave differently from those without cores.

With this newfound understanding, researchers assessed Vesta’s rotation and gravitational field.

The findings indicate that Vesta’s behavior contradicts previous notions about core formation.

“To confirm whether Vesta is an ancient remnant from a planetary formation, we need to develop more models and refine our analyses,” stated Dr. Jacobson.

“Scientists can also adapt their methodologies for studying Vesta’s materials to delve deeper into both hypotheses.”

“Further research can be conducted using innovative approaches to the Dawn mission data.”

“Our publications mark the beginning of a new research direction and could fundamentally alter how scientists perceive differentiated worlds.”

Read the paper published in the journal Natural Astronomy.

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RS Park et al. Vesta’s small core is inferred from Dawn’s observations. Nature Astronomy published online on April 23, 2025. doi:10.1038/s41550-025-02533-7