Although Ceres is the largest main-belt asteroid and was the first to be discovered (by G. Piazzi in 1801), its physical properties are still not well understood. While it is expected to have retained a large amount of primordial water ice in its interior, many questions about the composition of its surface and sub-surface layers, the properties of its regolith and its degree of differentiation, remain unanswered. A team of astronomers led by Benoit Carry of the Paris-Meudon Observatory used state-of-the-art adaptive optics instrumentation available at the Keck observatory, Mauna Kea, Hawaii, to image the surface of Ceres with a spatial resolution of about 30 km.
Article and Images @ Keck Observatory