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Mazeh, Holczer, and Shporer (2015) have presented an approach that can, inprinciple, use the derived transit timing variation (TTV) of some transitingplanets observed by the $Kepler$ mission to distinguish between prograde andretrograde motion of their orbits with respect to their parent stars' rotation.The approach utilizes TTVs induced by spot-crossing events that occur when theplanet moves across a spot on the stellar surface, looking for a correlationbetween the derived TTVs and the stellar brightness derivatives at thecorresponding transits. This can work even in data that cannot temporallyresolve the spot-crossing events themselves. Here we apply this approach to the$Kepler$ KOIs, identifying nine systems where the photometric spot modulationis large enough and the transit timing accurate enough to allow detection of aTTV-brightness-derivatives correlation. Of those systems five show highlysignificant prograde motion (Kepler-17b, Kepler-71b, KOI-883.01, KOI-895.01,and KOI-1074.01), while no system displays retrograde motion, consistent withthe suggestion that planets orbiting cool stars have prograde motion. All fivesystems have impact parameter $0.2\lesssim b\lesssim0.5$, and all systemswithin that impact parameter range show significant correlation, exceptHAT-P-11b where the lack of a correlation follows its large stellar obliquity.Our search suffers from an observational bias against detection of high impactparameter cases, and the detected sample is extremely small. Nevertheless, ourfindings may suggest that stellar spots, or at least the larger ones, tend tobe located at a low stellar latitude, but not along the stellar equator,similar to the Sun.

Time variation of Kepler transits induced by stellar spots - a way to distinguish between prograde and retrograde motion. II. Application to KOIs