  A planetary mass scale and a system of composition codes are presented for
describing the geophysical characteristics of exoplanets and Solar System
planets, dwarf planets, and spherical moons. The composition classes
characterize the rock, ice, and gas properties of planetary bodies. The
planetary mass scale includes five mass classes with upper and lower mass
limits derived from recent studies of the exoplanet mass radius and mass
density relationships and the physical characteristics of planets, dwarf
planets, and spherical moons in the Solar System. The combined mass and
composition codes provide a geophysical classification that allows for
comparison of the global mass and composition characteristics of exoplanets
with the Solar System's planets, dwarf planets, and spherical moons. The system
is flexible and can be combined with additional codes characterizing other
physical, dynamical, or biological characteristics of planets.
