They recently announced the first detection of an exo-moon, but said the moon was the same size as the Earth (orbiting a much larger gas planet) so the definiti

They recently announced the first detection of an exo-moon, but said the moon was the same size as the Earth (orbiting a much larger gas planet) so the definition of planet and moon is blurry. Unfortunately the terms 'dual-planets', 'double-planets', or 'binary-planets' are not (yet) recognized by the International Astronomical Union (IAU) according to wikipedia.