Spectroscopy and surface properties of (809) Lundia

International audienceTelescopic observation of binary system of (809) Lundia in the in the 0.8-2.5 mu m spectral range is presented in order to determine its physical and mineralogical parameters. Observations covering several oppositions were performed using NASA telescope Infrared Telescope Facility and SpeX spectrograph. One of these spectra was observed during a mutual event (an occultation between components). A detailed analysis of spectra was performed using M4AST tools. (809) Lundia complex is a V-type object having similar mineralogy on both components of the system. By applying different mineralogical models a composition similar to the one of howardite-diogenite meteorites was found. The comparison of composite visible and near-infrared spectra with meteorites from Relab data base confirms this solution. From this comparison a surface covered by fine dusty regolith with grain size less than 100 mu m was found. Orthopyroxene is the most abundant pyroxene of the regolith. Howarditic and diogenitic minerals seem to be the most abundant on the surface of (809) Lundia. The discrepancy between howardite-eucrite-diogenite meteorite bulk density and the one computed for the binary system suggests a rubble pile structure of both components