ALBEDO MAPS OF PLUTO AND IMPROVED PHYSICAL PARAMETERS OF THE PLUTO CHARON SYSTEM

We present an analysis of photometric observations of the Pluto-Charon rotational and mutual event light curves obtained between 1982 and 1990. The dataset covers 18 satellite transits (inferior events) and 15 eclipses/occultations of Charon (superior events). From these data we derive refined orbital and physical parameters of the binary system and a geometric albedo map of Pluto's sub-Charon hemisphere using a multiparameter least-squares-fit method. Independently from the eclipse data, we deconvolve the rotational light curve, yielding the longitudinal albedo distribution on Pluto near perihelion. Our albedo maps reveal a highly contrasted planetary surface, in agreement with earlier reports obtained by other authors using different datasets and techniques. In particular, we confirm that the brightest and darkest regions on Pluto are the south and north polar caps, respectively. The mean albedo decreases from the mid latitudes of the northern hemisphere toward the mid latitudes of the southern hemisphere. (C) 1994 Academic Press, Inc.