New Horizons REX Radiometry at Pluto and Charon

The thermal radio emission at 4.2 cm from Pluto and Charon was measured by radiometry observations as part of the REX investigation on New Horizons. As expected from its higher optical albedo, Charon was determined to be distinctly warmer than Pluto. The thermal emission from the dayside of both bodies was found to be stronger than on the nightside.