Methods for Simulating Comet Populations in Preparation for the Near-Earth Object Surveillance Mission

The Near-Earth Object Surveillance Mission (NEOSM) will provide unprecedented detection, tracking and characterization of Near-Earth Objects (NEOs) using high-cadence imaging from a space-based infrared telescope. Planning for the NEOSM requires an accurate model of the Solar System's small body populations in order to develop efficient operational survey strategies and to assess survey performance once in-flight operations have commenced. The NEOSM Investigation Team is currently developing the Reference Small Body Population Model (RSBPM; [1]) that will contain the current best estimates of the dynamical and physical properties of the Solar System's small body populations. Development of the RSBPM will be completed before the NEOSM launch, and the finished product will be peer-reviewed to ensure accuracy. Once the survey begins, we will compare predictions based on the RSBPM to actual observational measurements to calculate the efficiency of the survey, and thus de-bias the survey to properly characterize each population in order to assess Earth impact risks. We present here an update to the methods of incorporating comets into the RSBPM, with particular focus on accurately incorporating dust and CO+CO₂ gas comae activity behaviors. A better understanding of these physical characteristics is relevant for planetary defense (e.g., determining nuclei diameters). We are currently focusing on developing methods of modeling cometary activity behaviors utilizing derived: (1) nuclei cumulative size distributions, (2) dust activity behaviors as characterized by empirical trends of the ɛfρ parameter and (3) CO and CO₂ gas comae trends based on past and ongoing surveys. Future efforts by the NEOSM Investigation Team will focus on incorporation of other characteristic cometary phenomena (e.g., dust tails and trails) to help refine expected detection efficiencies and coma and/or tail flux removal for robust nucleus size estimation. NEOSM is a project sponsored by NASA's Planetary Defense Coordination Office, a division of NASA's Planetary Science Directorate. Gov't funding acknowledged.

1: Lilly (Schunova) et al., 2020, AAS Meeting Abstracts, 385.04.