2003/01/31 by E. I. Chiang, Eugene Chiang, A. B. Jordan +10 · 8 citations
Physics and Astronomy · #Astro and Planetary Science #Planetary Science and Exploration #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/375207
published as Astron.J. 126 (2003) 430 · Accepted to AJ, final version, contains list of names of all resonant KBOs known to humanity as of Feb 1 2003
arxiv created 2003/03/22 · openalex publication_date 2003/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1 : 1 (Trojan), 4 : 3, 3 : 2, 7 : 4, 2 : 1, and 5 : 2 Neptunian mean motion resonances (MMRs). The previously unrecognized occupation of the 1 : 1 and 5 : 2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Among all resonant Kuiper belt objects (KBOs), the three observed members of the 5 : 2 MMR discovered by DES possess the largest semimajor axes ( a ≈ 55.4 AU), the highest eccentricities ( e ≈ 0.4), and substantial orbital inclinations ( i ≈ 10°). Objects (38084) 1999HB 12 and possibly 2001KC 77 can librate with modest amplitudes of ∼90° within the 5 : 2 MMR for at least 1 Gyr. Their trajectories cannot be explained by close encounters with Neptune alone, given the latter's current orbit. The dynamically hot orbits of such 5 : 2 resonant KBOs, unlike hot orbits of previously known resonant KBOs, may imply that these objects were preheated to large inclination and large eccentricity prior to resonance capture by a migratory Neptune. Our first discovered Neptunian Trojan, 2001QR 322 , may not owe its existence to Neptune's migration at all. The trajectory of 2001QR 322 is remarkably stable; the object can undergo tadpole-type libration about Neptune's leading Lagrange (L4) point for at least 1 Gyr with a libration amplitude of 24°. Trojan capture probably occurred while Neptune accreted the bulk of its mass. For an assumed albedo of 12%–4%, our Trojan is ∼130–230 km in diameter. Model-dependent estimates place the total number of Neptune Trojans resembling 2001QR 322 at ∼20–60. Their existence helps to rule out violent orbital histories for Neptune.