Vesta's Polar Regions
New modeling shows that, under present conditions, Vesta's polar regions are cold enough (less than about 145 kelvins) to sustain water ice for billions of years, as this map of average surface temperature around the asteroid's south pole indicates. (The white dashed line marks Vesta's south polar circle.) Figure reprinted from the paper in Icarus by T.J. Stubbs, T.J. and Y. Wang.
Image credit: NASA/GSFC/UMBC