Illustration comparing the size of the largest known exoplanet, ROXs 42Bb (top right), with the planets of the Solar System. This planet is 2.6 times the radius of Jupiter. Other sub-stellar objects have been found that may be even bigger planets, but they could equally be brown dwarfs. As of April 2019, the gas giant ROX2 42Bb is the largest confirmed bona fide exoplanet.