COROT-Exo-1b, sometimes cataloged as CoRoT-Exo-1b or GSC 04804-02268b, is an extrasolar planet approximately 1,560 light-years away in the constellation of Monoceros. The planet was discovered orbiting the yellow dwarf star COROT-Exo-1 in May of 2007. The planet was the first discovery by the French-led COROT Mission.
The planet was announced by the COROT mission (a CNES project with European Space Agency participation). The planet, one of the largest ever known is an enormous hot jupiter, about 1.49 times the radius of Jupiter and approximately 1.03 times as massive, based on ground observations of the star. Its huge size is due to its low density combined with the intense heating of its parent star causing the outer layers of the atmosphere to bloat.