We measure the rotation periods of 19 stars in the Kepler transiting planetary systems , P _ { rot,astero } from asteroseismology and P _ { rot,phot } from photometric variation of their lightcurve .
Two stars exhibit two clear peaks in the Lomb-Scargle periodogram , neither of which agrees with the seismic rotation period .
Other four systems do not show any clear peak , whose stellar rotation period is impossible to estimate reliably from the photometric variation ; their stellar equators may be significantly inclined with respect to the planetary orbital plane .
For the remaining 13 systems , P _ { rot,astero } and P _ { rot,phot } agree within 30 % .
Interestingly , three out of the 13 systems are in the spin-orbit resonant state in which P _ { orb,b } / P _ { rot,astero } \approx 1 with P _ { orb,b } being the orbital period of the inner-most planet of each system .
The corresponding chance probability is ( 0.2 - 4.7 ) % based on the photometric rotation period data for 464 Kepler transiting planetary systems .
While further analysis of stars with reliable rotation periods is required to examine the statistical significance , the spin-orbit resonance between the star and planets , if confirmed , have important implications for the star-planet tidal interaction , in addition to the origin of the spin-orbit ( mis- ) alignment of transiting planetary systems .