Ceres
Images of the dwarf planet Ceres, which were taken by the spacecraft, reveal a white spot that reflects more sunlight. NASA scientists are not yet certain what this is but they have a hypothesis.

from techtimes.com

A series of new photos taken by NASA’s Dawn spacecraft of the dwarf planet Ceres on Jan. 13 reveals a and flickering white blotch on the extraterrestrial world that has baffled scientists.
Dawn, which was launched in 2007 to study the two largest objects in the asteroid belt, Vesta and Ceres, has captured photos revealing a white spot on Ceres as the probe approached the dwarf planet.
Scientists the Dawn mission, however, did not indicate what this mysterious dot is when Dawn’s new photos of Ceres were released on Jan. 19. Dawn mission director Marc Rayman acknowledged that there is something on the dwarf planet that reflects more light but said that what this is still remains a mystery.
Dawn has captured images that show light and dark areas on the of the planet indicating surface features such as craters but none of the specific features including the mysterious white dot can yet be resolved.
NASA’s Hubble Space Telescope has taken images of Ceres in 2003 and 2004, and the white spot also showed up in these images. While scientists are not yet certain what this is, the best hypothesis they currently have is that the distinct blotch is a frozen pool of water at a crater’s bottom that was clear enough to reflect sunlight.
Scientists are interested in studying Ceres because it is a unique and special in the solar . Having an average diameter of 590 miles, or about the size of Texas, it is the largest body in the main asteroid belt…