Through the careful analysis of the orbital period and radius of Charon's orbit in conjunction with Kepler's Third Law, the combine mass of Pluto and Charon can be determined by mathematical calculations. However, the present challenge of astronomers and scientists is to determine the individual masses of body.
The current techniques to approximate these figures involve the average separation and orbital period of the two bodies. To accurately determine the precise masses requires fine measurements of Pluto and Charon's orbiting motions around their center of mass. Since these bodies are so far away, it is immensely difficult to calculate these facts without the aid of a spacecraft. However, current data estimates Pluto's mass to be 6.4 x 10-9 solar masses. This is roughly seven times the mass of Charon and 0.0021 Earth's mass. The mass ratio is roughly in the range of 0.84 to 0.157.
Pluto has a density ranging from 1.8 to 2.1 grams per centimeter cubed (g/cm3), showing that the icy planet is composed of fifty to seventy five percent rock, with a mixture of fifty to twenty five ercent ice and water. These figures are close to Triton, possibly indicating a point of historical connection between the two bodies. On the albedo maps, the regions of high reflectivity are evidence of ice on Pluto, especially in the south polar region. The ice is probably composed of nitrogen with smaller amounts of methane and carbon dioxide.
Charon's density is in the range of 1.2 to 1.3 g/cm3, seemingly absent of rocky material. This difference indicates a separate origin from Pluto.
Mass and Density 
