WISE/NEOWISE Observations of the Jovian Trojans: Preliminary Results

TL;DR

This study analyzes NEOWISE observations of Jovian Trojans, significantly expanding data on their sizes, albedos, and beaming parameters, revealing a homogeneous population with low albedo and a leading cloud dominance.

Contribution

The paper provides the first large-scale infrared survey data of Jovian Trojans, increasing the known parameters by over an order of magnitude and offering new insights into their population distribution.

Findings

Jovian Trojans are mostly low albedo objects (~0.07).

The population is homogeneous for objects larger than ~10 km.

The leading cloud contains approximately 1.4 times more objects than the trailing cloud.

Abstract

We present the preliminary analysis of over 1739 known and 349 candidate Jovian Trojans observed by the NEOWISE component of the Wide-field Infrared Survey Explorer (WISE). With this survey the available diameters, albedos and beaming parameters for the Jovian Trojans have been increased by more than an order of magnitude compared to previous surveys. We find that the Jovian Trojan population is very homogenous for sizes larger than $\sim10$km (close to the detection limit of WISE for these objects). The observed sample consists almost exclusively of low albedo objects, having a mean albedo value of $0.07\pm0.03$. The beaming parameter was also derived for a large fraction of the observed sample, and it is also very homogenous with an observed mean value of $0.88\pm0.13$. Preliminary debiasing of the survey shows our observed sample is consistent with the leading cloud containing more objects than the trailing cloud. We estimate the fraction to be N(leading)/N(trailing) $\sim 1.4 \pm 0.2$, lower than the $1.6 \pm 0.1$ value derived by others.