Prediction of Planet Yields by the PRime-focus Infrared Microlensing Experiment Microlensing Survey

Abstract

Abstract The PRime-focus Infrared Microlensing Experiment (PRIME) will be the first to conduct a dedicated near-infrared microlensing survey by using a 1.8 m telescope with a wide field of view of 1.45 deg2 at the South African Astronomical Observatory. The major goals of the PRIME microlensing survey are to measure the microlensing event rate in the inner Galactic bulge to help design the observing strategy for the exoplanet microlensing survey by the Nancy Grace Roman Space Telescope and to make a first statistical measurement of exoplanet demographics in the central bulge fields where optical observations are very difficult owing to the high extinction in these fields. Here we conduct a simulation of the PRIME microlensing survey to estimate its planet yields and determine the optimal survey strategy, using a Galactic model optimized for the inner Galactic bulge. In order to maximize the number of planet detections and the range of planet mass, we compare the planet yields among four observation strategies. Assuming the Cassan et al. mass function as modified by Penny et al., we predict that PRIME will detect planetary signals for 42–52 planets (1–2 planets with M p ≤ 1M ⊕, 22−25 planets with mass 1M ⊕ < M p ≤ 100M ⊕, 19–25 planets 100M ⊕ < M p ≤ 10, 000M ⊕), per year depending on the chosen observation strategy.