Validation of the exoplanet Kepler-21b using PAVO/CHARA long-baseline interferometry

We present long-baseline interferometry of theKepler exoplanet host star HD 179070 (Kepler21) using the Precision Astronomical Visible Observations (PAVO) beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array. The visibility data are consistent with a single star and exclude stellar companions at separations ∼1–1000 mas (∼0.1–113 au) and contrasts <3.5 mag. This result supports the validation of the 1.6 R⊕ exoplanet Kepler-21b by Howell et al. and complements the constraints set by adaptive optics imaging, speckle interferometry and radial-velocity observations to rule out false positives due to stellar companions. We conclude that long-baseline interferometry has strong potential to validate transiting extrasolar planets, particularly for future projects aimed at brighter stars and for host stars where radial-velocity follow-up is not available.