The Whole Iceberg: Completing the Census of Exoplanets with the WFIRST Microlensing Survey

The Wide Field Infrared Survey Telescope (WFIRST) will be NASA's next flagship mission to follow James Webb. Roughly a quarter of WFIRST's primary mission will be spent conducting an exoplanet microlensing survey. The survey will provide a statistical assay of the cold exoplanet population with masses greater than that of Mars and orbits beyond ~1 AU, with a total planet yield comparable to Kepler's. It will also measure the mass function of free-floating planets potentially down into the mass regime of large Kuiper Belt Objects. The WFIRST microlensing survey parameter space spans critical mass and distance scales in planet formation theories, including the ice line, the isolation mass, and the critical mass for runaway gas accretion. After a brief introduction to the microlensing technique I will give an overview of the WFIRST microlensing survey, highlights of its expected results, and introduce various ongoing efforts to ensure its success. I will also describe the legacy value of the WFIRST microlensing data set of high-cadence near-infrared lightcurves of ~200 million stars, which will be useful for guest investigators interested in topics as varied asteroseismology, astrometry, Galactic structure, warm transiting planets, and stellar-mass black holes.

Speaker: Matthew Penny, The Ohio State University