Observation of two new L4 Neptune Trojans in the Dark Energy Survey supernova fields

Abstract

We report the discovery of the eighth and ninth known Trojans in stable orbits around Neptune’s leading Lagrange point, L4. The objects 2014QO441 and 2014QP441 were detected in data obtained during the 2013–14 and 2014–15 observing seasons by the Dark Energy Survey, using the Dark Energy Camera (DECam) on the 4-m Blanco telescope at Cerro Tololo Inter-American Observatory. Both are in high-inclination orbits (18°.8 and 19°.4, respectively). With an eccentricity of 0.104, 2014QO441 has the most eccentric orbit of the 11 known stable Neptune Trojans. Here we describe the search procedure and investigate the objects’ long-term dynamical stability and physical properties.