Minerva May be Structurally Unique Among Asteroids

Since the discovery of its two moons, the triple asteroid Minerva has been the focus of space and ground-based telescope studies that have attempted to unravel the secrets of this intriguing system. Several groups of scientists has revealed that Minerva is unusually round for an asteroid, and has a possibly unique structure. Minerva is the fourth asteroid located in the main-belt known to possess two moons. With a diameter of 156 km and two tiny 5-km size moons, this triple system orbits around the Sun between Mars and Jupiter. The two moons were discovered in 2009 using the Keck II telescope by members of this team. From the shape, size, and mass of the asteroid, the astronomers calculated its density to be 1.9 grams per cubic centimeter. 

Minerva appears to be a primitive type of asteroid known as a carbonaceous chondrite. According to researchers Minerva has a significantly higher density than other carbonaceous-type asteroids in multiple systems. So they may finally detect subtle differences in the compositions of these types of asteroids by studying the composition of carbonaceous chondrite meteorites. These results may provide insight not only into the history and formation of multiple asteroid systems but also the structure and origin of asteroids in general.