Enriching Our View of Multiplanet Systems Using TESS

Multiplanet systems have been found to be extremely common and, at least for small planets, highly coplanar. The mutual inclinations, multiplicity, and morphology of multiplanet systems are valuable probes of planet composition and formation. We report on results from our accepted TESS Cycle 3 proposal to enrich the sample of multiplanet systems by obtaining 20-sec cadence observations of 915 relatively bright stars known to host one or more planets or planet candidates. Thus far we have already systematically searched these light curves and detected hundreds of threshold crossing events (TCEs) with no previously known planet or candidate counterpart. We report here on the vetting and validation status of these TCEs and place them within the context of known multiplanet systems. The goals of our investigation are to (1) discover additional planets in these systems by detecting transits and transit timing variations (TTVs); (2) increase the sample of long-period planets by detecting single transit events and estimating the orbital parameters of planets with uncertain orbital periods; (3) perform follow-up analyses of TESS photometry to assess the robustness of planet candidates; (4) obtain ground-based observations as needed to validate planet candidates; (5) constrain masses of known and newly discovered planets via TTVs; (6) identify promising targets for atmospheric characterization; (7) use our catalog of newly detected planets and newly estimated planet masses and densities to investigate system formation and architecture.