TOI-822.02 is a Nearby Planetary Companion to Hot Jupiter WASP-132 b

Hot Jupiters are generally thought to lack close planetary companions, a trend that has been interpreted as evidence for high-eccentricity migration. We present the discovery and validation of TOI-822.02, a 1.78 ± 0.10 R_Earth planet on a 1.01 day orbit interior to the hot Jupiter WASP-132 b. Transiting Exoplanet Survey Satellite (TESS) 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 TOI-822.02 as a planet, dubbed here as WASP-132 c. Running the validation tools VESPA and TRICERATOPS on this signal yield false positive probabilities of 9×10^-5 and 0.0107, respectively. Analysis of archival CORALIE radial velocity data leads to a 3s upper limit of 24.7 ms^-1 on the amplitude of any 1.01-day signal, corresponding to a 3s upper mass limit of 32.65 M_Earth. Dynamical simulations reveal that the system is stable within the 3s uncertainties on 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. WASP-132 c represents one of just a handful of nearby planetary companions to hot Jupiters, carrying with it implications for the formation of the system and hot Jupiters as a population. A uniform search for additional systems with similar architecture is ongoing utilizing data from the TESS extended mission. This will enable further refinement of the occurrence rate of these nearby companion planets to hot Jupiters.