Composition of near-Earth Asteroid 2008 EV5: Potential target for robotic and human exploration

We observed Potentially Hazardous Asteroid (PHA) 2008 EV5 in the visible (0.30-0.92 mu m) and near-IR (0.75-2.5 mu m) wavelengths to determine its surface composition. This asteroid is especially interesting because it is a potential target for two sample return mission proposals (Marco Polo-R and Hayabusa-2) and human exploration due to its low delta-v for rendezvous. The spectrum of 2008 EV5 is essentially featureless with exception of a weak 0.48-mu m spin-forbidden Fe3+ absorption band. The spectrum also has an overall blue slope. The albedo of 2008 EV5 remains uncertain with a lower limit at 0.05 and a higher end at 0.20 based on thermal modeling. The Busch et al. (Busch et al. [2011]. Icarus 212, 649-660) albedo estimate of 0.12 +/- 0.04 is consistent with our thermal modeling results. The albedo and composition of 2008 EV5 are also consistent with a C-type taxonomic classification (Somers, J.M., Hicks, M.D., Lawrence, K.J. [2008]. Bull. Am. Astron. Soc. 40, 440). The best spectral match is with CI carbonaceous chondrites similar to Orgueil, which also have a weak 0.48-mu m feature and an overall blue slope. This 0.48-mu m feature is also seen in the spectrum of magnetite. The albedo of Cl chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5. (C) 2012 Elsevier Inc. All rights reserved.