Tokyo Institute of Technology | via EurekAlert | 2019 Jun 11
A massive 'hit-and-run' collision profoundly impacted the evolutionary history of Vesta, the brightest asteroid visible from Earth. This finding ... deepens our understanding of protoplanet formation more than 4.5 billion years ago, in the early infancy of the Solar System.
In a remarkable feat of astronomical detective work, scientists have determined the precise timing of a large-scale collision on Vesta that helps explain the asteroid's lopsided shape. Their study ... pinpoints the collision to 4,525.4 million years ago.
Vesta, the second largest body in the asteroid belt, is of immense interest to scientists investigating the origin and formation of planets. Unlike most asteroids, it has kept its original, differentiated structure, meaning it has a crust, mantle and metallic core, much like Earth.
Most of what we know about the asteroid had so far come from howardite-eucrite-diogenite (HED) meteorites, following studies in the 1970s that first proposed Vesta as the parent body of these meteorites. In recent years, NASA's Dawn mission, which orbited Vesta in 2011-2012, reinforced the idea that HED meteorites originate from Vesta and provided more insights into the asteroid's composition and structure. Careful mapping of Vesta's geology revealed an unusually thick crust at the asteroid's south pole.
The new study provides a confident framework for understanding Vesta's geological timeline, including the massive collision that caused the formation of the thick crust.
Mesosiderite Formation on Asteroid 4 Vesta by a Hit-and-Run Collision ~ Makiko K. Haba et al
- Nature Geoscience (online 10 Jun 2019) DOI: 10.1038/s41561-019-0377-8