Global Albedos of Pluto and Charon from LORRI New Horizons Observations

Global Albedos of Pluto and Charon from LORRI New Horizons Observations

Authors:

Burratti et al

Abstract:

The exploration of the Pluto-Charon system by the New Horizons spacecraft represent the first opportunity to understand the distribution of albedo and other photometric properties of the surfaces of objects in the Solar System's "Third Zone" within the context of a geologic world. Images of the entire illuminated surface of Pluto and Charon obtained by the Long Range Reconnaissance Imager (LORRI) camera provide a global map of Pluto that revealed surface albedo variegations larger than any other world except for Saturn's moon Iapetus. Normal reflectances on Pluto range from 0.08-1.0. Charon exhibits a much blander surface with normal reflectances ranging from 0.20-0.73. Pluto's albedo features are well-correlated with geologic features, although some exogenous low-albedo dust may be responsible for features seen to the west of the area informally named Tombaugh Regio. The albedo patterns of both Pluto and Charon are latitudinally organized, with the exception of Tombaugh Regio. The low-albedo areas of Pluto are darker than anything on Charon's surface. The phase curve of Pluto is similar to that of Triton, the large moon of Neptune, and a former KBO dwarf planet, while Charon's is similar to that of the Moon. Preliminary Bond albedos are 0.25 +/- 0.03 for Charon and 0.72 +/- 0.07 for Pluto. Maps of the Bond albedo for both Pluto and Charon are presented for the first time.