Thermophysical properties of near-Earth asteroid (341843) 2008 EV5 from WISE data⋆
1 Instituto de Astrofísica de Canarias (IAC), c/ Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
2 Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
3 University Paris VII – Diderot, 5 rue Thomas Mann, 75013 Paris, France
4 UNS-CNRS-Observatoire de la Côte d’Azur, BP 4229, 06304 Nice Cedex 4, France
5 Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
Received: 5 July 2013
Accepted: 23 October 2013
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 pV = 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.
Key words: minor planets, asteroids: individual: (341843) 2008 EV5 / infrared: planetary systems / radiation mechanisms: thermal
Table of observed fluxes is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (184.108.40.206) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A45
© ESO, 2013