Validation of the Exoplanet Kepler-21b using PAVO/CHARA Long-Baseline Interferometry

TL;DR

This study uses long-baseline interferometry to confirm that Kepler-21 is a single star, supporting the validation of its exoplanet Kepler-21b and demonstrating the method's potential for future planet validation efforts.

Contribution

It provides the first interferometric validation of Kepler-21b, showing the effectiveness of long-baseline interferometry in exoplanet validation.

Findings

Kepler-21 shows no stellar companions within 0.1-113 AU.

Supports the validation of Kepler-21b as a planet.

Highlights interferometry's potential in exoplanet validation.

Abstract

We present long-baseline interferometry of the Kepler exoplanet host star HD179070 (Kepler-21) using the PAVO beam combiner at the 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 magnitudes. This result supports the validation of the 1.6 R_{earth} exoplanet Kepler-21b by Howell et al. (2012) 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.