Thermal properties of asteroid 21 Lutetia from Spitzer Space Telescope observations

Asteroid 21 Lutetia is the second target of the Rossetta space mission, with a flyby scheduled on July 10, 2010. Lamy et al. use Spitzer observations of the asteroid to understand its thermal properties. They predict that its surface should be covered by a thick regolith layer and have a high degree of rugosity. The images below show simulated visible (B&W) and thermal (in color) images of the asteroid at different moments of the Rosetta flyby.