2018AJ....155..210M

We show that the claimed confirmed planet Kepler-452b (a.k.a., K07016.01, KIC 8311864) cannot be confirmed using a purely statistical validation approach. Kepler detects many more periodic signals from instrumental effects than it does from transits, and it is likely impossible to confidently distinguish the two types of events at low signal-to-noise. As a result, the scenario that the observed signal is due to an instrumental artifact cannot be ruled out with 99% confidence, and the system must still be considered a candidate planet. We discuss the implications for other confirmed planets in or near the habitable zone.