Photometry And Surface Mapping Of Asteroid Itokawa From Hayabusa Nirs Observations

The near-infrared spectrometer (NIRS) on the Hayabusa spacecraft obtained more than 80,000 spatially resolved 800- to 2200-nm reflectance spectra of 25143 Itokawa between September 12 and November 24, 2005. Spectra were obtained over a range of phase angles from near 0 to 38 degrees, which allowed constructing a photometric model of the asteroid's surface. A strong opposition surge at low phase angles and phase reddening were detected. After a photometric correction of the spectral data using Hapke modeling, we produced an albedo map on Itokawa surface and found a nearly 10% of albedo variation from space weathering, particle size, and/or heterogeneity of the composition.