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

TL;DR

The PRIME infrared microlensing survey aims to measure microlensing event rates and exoplanet demographics in the Galactic bulge, predicting the detection of 42-52 planets annually through simulation-based optimization of observation strategies.

Contribution

This study provides the first simulation-based estimate of exoplanet yields for the PRIME infrared microlensing survey, optimizing observation strategies for maximum planet detection.

Findings

PRIME will detect 42-52 planets per year depending on strategy.

It will identify planets across a wide mass range, including Earth-mass planets.

Optimal strategies significantly influence detection rates.

Abstract

The PRime-focus Infrared Microlensing Experiment (PRIME) will be the first to conduct a dedicated near infrared (NIR) microlensing survey by using a 1.8m telescope with a wide field of view of 1.45 ${\rm deg^{2}}$ at the South African Astronomical Observatory (SAAO). 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 {\it 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 \citet{2012Natur.481..167C} mass function as modified by \citet{2019ApJS..241....3P}}, we predict that PRIME will detect planetary signals for $42-52$ planets ($1-2$ planets with $M_p \leq 1 M_\oplus$, $22-25$ planets with mass $1 M_\oplus < M_p \leq 100 M_\oplus$, $19-25$ planets $100 M_\oplus < M_p \leq 10000 M_\oplus$), per year depending on the chosen observation strategy.