Physical properties of 299 NEOs manually recovered in over five years of NEOWISE survey data

Abstract

Thermal infrared measurements of near-Earth objects (NEOs) provide critical data for constraining their physical properties such as size. The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission has been conducting an all-sky infrared survey to gather such data and to improve our understanding of this population. While automated routines are employed to identify the majority of moving objects detected by NEOWISE, a subset of objects will have dynamical properties that fall outside the window detectable to these routines. Using the population of known NEOs, we have conducted a manual search for detections of these objects that were previously unreported. We report 303 new epochs of observations for 299 unique NEOs of which 239 have no previous physical property characterization from the NEOWISE Reactivation mission. As these objects are drawn from a list with inherent optical selection biases, the distribution of measured albedos is skewed to higher values than is seen for the diameter-selected population detected by the automated routines. These results demonstrate the importance and benefit of periodic searches of the archival NEOWISE data.