We report the discovery of KELT-3b , a moderately inflated transiting hot Jupiter with a mass of 1.477 _ { -0.067 } ^ { +0.066 } M _ { J } , and radius of 1.345 \pm 0.072 R _ { J } , with an orbital period of 2.7033904 \pm 0.000010 days .
The host star , KELT-3 , is a V = 9.8 late F star with M _ { * } = 1.278 _ { -0.061 } ^ { +0.063 } M _ { \odot } , R _ { * } = 1.472 _ { -0.067 } ^ { +0.065 } R _ { \odot } , T _ { eff } = 6306 _ { -49 } ^ { +50 } K , log ( g ) = 4.209 _ { -0.031 } ^ { +0.033 } , and [ Fe/H ] = 0.044 _ { -0.082 } ^ { +0.080 } , and has a likely proper motion companion .
KELT-3b is the third transiting exoplanet discovered by the KELT survey , and is orbiting one of the 20 brightest known transiting planet host stars , making it a promising candidate for detailed characterization studies .
Although we infer that KELT-3 is significantly evolved , a preliminary analysis of the stellar and orbital evolution of the system suggests that the planet has likely always received a level of incident flux above the empirically-identified threshold for radius inflation suggested by \citet ds11 .