Vesta—Ceres' little sister
Only around 60 million kilometres closer to the Sun than Ceres, another large rock is orbiting in the remote asteroid belt: Vesta. Although its diameter of approximately 530 kilometres makes it a bit too small to be counted as a dwarf planet, it is nevertheless big enough to be the second heaviest and third largest body in this region between the orbits of Mars and Jupiter. Ceres' little sister has already gone through what is in store for the asteroid in the coming months: As the first destination of the US Dawn mission, the spacecraft's three onboard measuring instruments subjected Vesta to more than a year of permanent monitoring from July 2011 to September 2012. As it turned out: Vesta was originally well on its way to developing into a planet.