Characterizing Subpopulations within the Near Earth Objects with NEOWISE: Preliminary Results

TL;DR

This study uses NEOWISE data to analyze near-Earth asteroid subpopulations, estimating their numbers, albedo differences, and size distributions, providing insights into potentially hazardous objects and their orbital characteristics.

Contribution

It introduces a method to correct for survey biases in NEOWISE data, enabling more accurate estimates of NEO subpopulation sizes and properties.

Findings

Approximately 4700±1450 potentially hazardous asteroids larger than 100 m.

Atens are brighter than Amors, indicating different albedo distributions.

Size distributions of NEO subgroups vary slightly between 100 m and 1 km.

Abstract

We present the preliminary results of an analysis of the sub-populations within the near-Earth asteroids, including the Atens, Apollos, Amors, and those that are considered potentially hazardous using data from the Wide-field Infrared Survey Explorer (WISE). In order to extrapolate the sample of objects detected by WISE to the greater population, we determined the survey biases for asteroids detected by the project's automated moving object processing system (known as NEOWISE) as a function of diameter, visible albedo, and orbital elements. Using this technique, we are able to place constraints on the number of potentially hazardous asteroids (PHAs) larger than 100 m and find that there are $\sim4700\pm1450$ such objects. As expected, the Atens, Apollos, and Amors are revealed by WISE to have somewhat different albedo distributions, with the Atens being brighter than the Amors. The cumulative size distributions of the various near-Earth object (NEO) subgroups vary slightly between 100 m and 1 km. A comparison of the observed orbital elements of the various sub-populations of the NEOs with the current best model is shown.