CONICET | Buscador de Institutos y Recursos Humanos

The results of the in situ exploration of the asteroid (4) Vesta by the Dawn spacecraft opennew perspectives in the field of interpretation of remote-sensing polarimetric measurements ofasteroids. (4) Vesta has long been known to be the only asteroid exhibiting a cyclic variationof the degree of linear polarization of the sunlight scattered by its surface, with a period whichis synchronous with the object?s rotation. This variation must be the consequence of someheterogeneity of the asteroid?s surface, including regions characterized by different albedo,or composition, or regolith properties, or a combination of the above features. For a longtime, this kind of conclusion has remained essentially qualitative. Now, after the extensiveexploration of Vesta?s surface by Dawn, it is possible to interpret the data set of polarimetricmeasurements of Vesta, including some unpublished data presented here for the first time, interms of a correspondence between the degree of linear polarization and the variation of localproperties of the surface visible to ground-based observers during Vesta?s rotation, as seen atdifferent epochs and under different illumination conditions. This makes it possible to refineour knowledge of the empirical relation between polarization properties and albedo, which iscommonly used to derive the albedo from remote-sensing measurements of linear polarizationof atmosphereless Solar system bodies.