New images released by NASA have provided scientists their best view yet of the black spots seen on the surface of the giant asteroid Vesta. The new research suggests that the protoplanet may have received the carbon-rich material through large impacts with other objects.

The new study, published in the journal Icarus, is the most complete analysis of the material yet. Researchers observed that the dark material appears around the edges of giant impact basins on the asteroid’s southern hemisphere, suggesting that the material was deposited by the impact that created the older of the two basins.

“First, we created a map showing the distribution of dark material on Vesta using the framing camera data and found something remarkable,” said Lucille Le Corre, co-author of the study at the Max Planck Institute for Solar System Research.

The map showed that the material had been spread by a slow impacting asteroid that created the Veneneia basin some 2 to 3 billion years ago. The material was then covered by a subsequent impact that created the younger basin.

The images were taken by NASA’s Dawn mission, which completed its investigations of Vesta in September 2012 and is currently on-route to the dwarf planet Ceres. In the past few months, research based on Dawn mission data has uncovered strange gullies along the walls of Vesta craters and the fact that Vesta’s surface is constantly “stirring” and presenting a young sppearance.

“The aim of our efforts was not only to reconstruct Vesta’s history, but also to understand the conditions in the early solar system,” said Holger Sierks, co-investigator on the Dawn mission at the Max Planck Institute.

(Image courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)