WISE/NEOWISE OBSERVATIONS OF THE JOVIAN TROJANS: PRELIMINARY RESULTS

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 (Tedesco et al. 1992(Tedesco et al. , 2002Fernández et al. 2003Fernández et al. , 2009Ryan & Woodward 2010). We find that the Jovian Trojan population is very homogenous for sizes larger than ∼ 10km (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 ± 0.03. 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 ± 0.13.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) ∼ 1.4 ± 0.2, lower than the 1.6 ± 0.1 value derived by Szabó et al. (2007).

Space-Based Thermal Infrared Studies of Asteroids

“…Mainzer et al (2011dMainzer et al ( , 2012a; ; for the NEOs; Masiero et al (2011Masiero et al ( , 2012aMasiero et al ( , 2014 for the MBAs; Grav et al (2011bGrav et al ( , 2012a for the Hilda group and Jovian Trojans; and Bauer et al (2013) for the scattered disk objects and Centaur populations. Data from the NEOWISE reactivation will be publicly released annually through IRSA beginning in March 2015.…”

“…Since high radar albedos can correspond to high metal content, follow-up radar observations are desirable to confirm their nature. NEOs tend to have higher η values than MBAs and Jovian Trojans; this may indicate higher thermal inertia, although they are often observed at higher phase angles than MBAs (Delbó et al 2007;Mainzer et al 2011d;Masiero et al 2011;Grav et al 2011b). Bauer et al (2013) used WISE to perform thermal modeling on 52 Centaurs and scattered disk objects, finding that most η values were low and similar to those of bare cometary nuclei, suggesting a common origin.…”

Four temporary Neptune co-orbitals: (148975) 2001 XA255, (310071) 2010 KR59, (316179) 2010 EN65, and 2012 GX17

“…4-6). Dynamically speaking, they are similar to the recently identified temporary Neptunian quasi-satellite (309239) Out of more than 5000 confirmed Jupiter Trojans there is a well-documented asymmetry between the number of bodies in the leading and trailing populations: the Sloan Digital Sky Survey (SDSS) puts the L 4 :L 5 Trojan ratio at 1.6 ± 0.1 (Szabó et al 2007), the Subaru telescope survey gives nearly 1.8 ) and the latest results from the WISE/NEOWISE mission give 1.4 ± 0.2 (Grav et al 2011). Prior to this research the L 4 :L 5 ratio for Neptune was 6/3 = 2.…”

A Panoramic View of the Asteroids in the Inner Solar System With Akari

“…The WISE asteroid database is only a preliminary version at present (Mainzer et al, 2011;Masiero et al, 2011;Grav et al, 2011Grav et al, , 2012 and further processing is currently underway before the final public version will be available. It will include more than 130,000 asteroids, which corresponds to over 20% of asteroids with known orbits.…”