2012 LA, an optimal astrometric target for radiation pressure detection

We present our dynamical analysis of near-Earth object 2012 LA, derived from a collection of astrometric positions obtained by us with telescopes on Mauna Kea, in Hawaii, densely covering the entire 2012 apparition of the object. Clear evidence of non-gravitational acceleration, attributable to radiation pressure, is present in the complete dataset, but would not be detectable with the sparse sampling of the apparition obtained by other stations. Our determination of the Area to Mass Ratio of A/m = (0.335 ± 0.028) × 10−3 m2/kg is the most significant detection of radiation pressure obtained to date on any natural object. This value can be converted into a bulk density estimate of ρ=460-210+260kg/m3, under certain assumptions on size, albedo and shape.