Improved orbital and physical parameters for the Pluto-Charon system

by: Tholen, D. J.; Buie, M. W.; Binzel, R. P.; Frueh, M. L.

ABSTRACT

Analysis of the observations of several Pluto-Charon occultation and
transit events in 1985 and 1986 has provided a more detailed knowledge
of the system. The sum of the radii of Pluto and Charon is 1786 or - 19
kilometers, but the individual radii are somewhat more poorly determined
Pluto is 1145 or - 46 kilometers in radius, and Charon is 642 or - 34
kilometers in radius. The mean density of the system is 1.84 or - 0.19
grams cu cm, implying that more than half of the mass is due to rock.
Charon appears to have hemispheres of two different colors, the Pluto-
facing side being neutral in color and the opposite hemisphere being a
reddish color similar to Pluto.

Science, ISSN 0036-8075, vol. 237, July 31, 1987, p. 512-514.