The Discovery of a Planetary Companion Interior to Hot Jupiter WASP-132 b

Abstract

<jats:title>Abstract</jats:title> <jats:p>Hot Jupiters are generally observed to lack close planetary companions, a trend that has been interpreted as evidence for high-eccentricity migration. We present the discovery and validation of WASP-132 c (TOI-822.02), a 1.85 ± 0.10 <jats:italic>R</jats:italic> <jats:sub>⊕</jats:sub> planet on a 1.01 day orbit interior to the hot Jupiter WASP-132 b. Transiting Exoplanet Survey Satellite and ground-based follow-up observations, in conjunction with vetting and validation analysis, enable us to rule out common astrophysical false positives and validate the observed transit signal produced by WASP-132 c as a planet. Running the validation tools <jats:monospace>vespa</jats:monospace> and <jats:monospace>TRICERATOPS</jats:monospace> on this signal yields false-positive probabilities of 9.02 × 10<jats:sup>−5</jats:sup> and 0.0107, respectively. Analysis of archival CORALIE radial velocity data leads to a 3<jats:italic>σ</jats:italic> upper limit of 28.23 ms<jats:sup>−1</jats:sup> on the amplitude of any 1.01 day signal, corresponding to a 3<jats:italic>σ</jats:italic> upper mass limit of 37.35 <jats:italic>M</jats:italic> <jats:sub>⊕</jats:sub>. Dynamical simulations reveal that the system is stable within the 3<jats:italic>σ</jats:italic> uncertainties on the planetary and orbital parameters for timescales of ∼100 Myr. The existence of a planetary companion near the hot Jupiter WASP-132 b makes the giant planet’s formation and evolution via high-eccentricity migration highly unlikely. Being one of just a handful of nearby planetary companions to hot Jupiters, WASP-132 c carries with it significant implications for the formation of the system and hot Jupiters as a population.</jats:p>