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 μm) and near-IR (0.75-2.5 μm) 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-μm 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-μm feature and an overall blue slope. This 0.48-μm feature is also seen in the spectrum of magnetite. The albedo of CI chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5.