Kepler-13Ab ( = KOI-13.01 ) is a unique transiting hot Jupiter .
It is one of very few known short-period planets orbiting a hot A-type star , making it one of the hottest planets currently known .
The availability of Kepler data allows us to measure the planet ’ s occultation ( secondary eclipse ) and phase curve in the optical , which we combine with occultations observed by warm Spitzer at 4.5 \mu m and 3.6 \mu m and a ground-based occultation observation in the K _ { s } band ( 2.1 \mu m ) .
We derive a day-side hemisphere temperature of 2,750 \pm 160 K as the effective temperature of a black body showing the same occultation depths .
Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion .
Our analysis shows evidence for a relatively high geometric albedo , A _ { g } = 0.33 ^ { +0.04 } _ { -0.06 } .
While measured with a simplistic method , a high A _ { g } is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical .
We use stellar spectra to determine the dilution , in the four wide bands where occultation was measured , due to the visual stellar binary companion 1 \farcs 15 \pm 0 \farcs 05 away .
The revised stellar parameters measured using these spectra are combined with other measurements leading to revised planetary mass and radius estimates of M _ { p } = 4.94–8.09 M _ { J } and R _ { p } = 1.406 \pm 0.038 R _ { J } .
Finally , we measure a Kepler mid-occultation time that is 34.0 \pm 6.9 s earlier than expected based on the mid-transit time and the delay due to light travel time , and discuss possible scenarios .