Kelt-9b is an extrasolar planet orbits the star Kelt-9. It is a hot Jupiter that is one of the hottest planets known. The planet is also one of the largest planets known, and is located 670 light years away from earth. Kelt-9b is also tidally locked to its host star, meaning that one side always faces its star. also The surface temperature of the host star, KELT-9, is 10,170 K, unusually hot for a star with a transiting planet. Prior to the discovery of KELT-9b, only six A-type stars were known