Thermophysical properties of near-Earth asteroid (341843) 2008 EV5 from WISE data

Aims: We derive the thermal inertia of 2008 EV₅, the baseline target for the Marco Polo-R mission proposal, and infer information about the size of the particles on its surface.
Methods: Values of thermal inertia were obtained by fitting an asteroid thermophysical model to NASA's Wide-field Infrared Survey Explorer (WISE) infrared data. Grain size was derived from the constrained thermal inertia and a model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles).
Results: We obtain an effective diameter D = 370 ± 6 m, geometric visible albedo p_V = 0.13 ± 0.05 (assuming H = 20.0 ± 0.4), and thermal inertia Γ = 450 ± 60 J m^-2 s^-1/2 K^-1 at the 1σ level of significance for its retrograde spin-pole solution. The regolith particles radius is r = 6.6^+1.3_-1.3 mm for low degrees of compaction and r = 12.5^+2.7_-2.6 mm for the highest packing densities.

Table of observed fluxes is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A45