High Quality Content by WIKIPEDIA articles! Pallas, formally designated 2 Pallas, is the second asteroid to have been discovered (after Ceres), and one of the largest. It is estimated to constitute 7% of the mass of the asteroid belt, and its diameter of 530–565 km is comparable to, or slightly larger than, that of 4 Vesta. It is however 20% less massive than Vesta, placing it third among the asteroids. It is possibly the largest irregularly shaped body in the Solar System (that is, the largest body not rounded under its own gravity), and a remnant protoplanet.