The surface of the solar system’s largest asteroid, Ceres, has been mapped in infrared light in fine detail for the first time. The feat will pave the way for a better determination of the surface composition of Ceres, whose interior is believed to be 25% water ice. The 950-kilometre-wide space rock lies in the main asteroid belt between Mars and Jupiter and is massive enough for its gravity to make it a sphere, a quality that nearly earned it planetary status in August 2006. The Hubble Space Telescope took visible light images of Ceres in 2003 and 2004 and also mapped the asteroid in ultraviolet light in 2001. These images show bright and dark patches on the asteroid, but astronomers still do not know exactly what the patches represent. Now astronomers led by Benoit Carry of the Paris-Meuden Observatory in France have taken a step towards solving the mystery by obtaining the first high-resolution images of Ceres in infrared light, which is better than visible or UV light at distinguishing chemicals. They used the Keck II telescope atop Mauna Kea in Hawaii to obtain the images, which show features as small as 30 kilometres across. The infrared images show bright and dark patches that closely match what Hubble saw in visible light.
Source:
Surface mapping of asteroid Ceres with the Keck AO system
Carry, B., Dumas, C., Fulchignoni, M., Merline, W.
Presented at the 38th Annual Meeting of the Division for Planetary Sciences in Pasadena, California, October 8-13, 2006.
Images of Dwarf Planet Ceres