In astronomy,
double planet (also
binary planet) is a
binary system where both
objects are of
planetary mass. The term is not recognized by the
International Astronomical Union and is therefore not an official classification. At its 2006 General Assembly, the International Astronomical Union considered a proposal that
Pluto and
Charon be reclassified as a double planet, but the proposal was abandoned in favor of the current definition of
planet. In promotional materials advertising the
SMART-1 mission and pre-dating the IAU planet definition, the
European Space Agency once referred to the
Earth–
Moon system as a double planet.