Spurious Oscillatory Signal in Kepler Eclipsing Binary Light Curves

Abstract In our study of the O’Connell effect in Kepler eclipsing binaries, we found that some systems display a spurious oscillatory signal in their long-cadence light curves. This signal occurred in 12% of our sample of 258 systems. The cause of this signal is a resonance between the binary’s orbital period and Kepler’s integration time. We found that binaries that have an orbital period that is close to (within ∼1%) an integer multiple or a simple fraction of the effective long-cadence integration time of 1765.5 s displayed an oscillatory signal. In this note, we highlight this phenomenon due to its potential impact on research using Kepler data, especially the study of pulsating variable stars.