The Completion of the Distant Giants Survey

We present the recently-completed Distant Giants Survey, a 3-year radial velocity (RV) survey designed to estimate the conditional occurrence of long-period Jupiter analogs in systems hosting small transiting planets. NASA’s Kepler Space Telescope taught us that small close-in planets occur at a rate of ~1 per Sun-like star. Meanwhile, ground-based RV surveys have shown that long-period gas giants are relatively rare, with an occurrence rate of ~0.1-0.2 per Sun-like star. Because there is so little overlap between these two stellar samples, the connection between inner small planets and distant giants is poorly understood. The Distant Giants Survey, which began in late 2020, observed 47 stars with small transiting planets discovered by NASA’s TESS mission, searching for RV signatures of large outer planets. We detected evidence of distant companions in 15 of these systems, including 4 Jupiter analogs with orbits beyond 1 year. Many candidate detections have orbital periods much longer than the current observing baseline, exhibiting “trends” in their RV time series. We introduce a forward modeling technique, implemented as a pip-installable Python package, to constrain the properties of long-period companions by combining RVs, astrometry, and direct imaging, and apply it to these trend systems. With our full sample of over 4000 RV measurements, we find weak evidence of an enhancement of distant giants in systems with close-in small planets. This finding will help to refine exoplanet formation models and determine whether the solar system’s architecture is a common outcome of exosystem evolution.