OSSOS: The Eccentricity and Inclination Distributions of the Stable Neptunian Trojans

Abstract

The minor planets on orbits that are dynamically stable in Neptune's 1:1 resonance on Gyr timescales were likely emplaced by Neptune's outward migration. We explore the intrinsic libration amplitude, eccentricity, and inclination distribution of Neptune's stable Trojans, using the detections and survey efficiency of the Outer Solar System Origins Survey (OSSOS) and Pan-STARRS1. We find that the libration amplitude of the stable Neptunian Trojan population can be well modeled as a Rayleigh distribution with a libration amplitude width ${\sigma }_{A_{p}hi}$ of 15${}^{\circ }$. When taken as a whole, the Neptune Trojan population can be acceptably modeled with a Rayleigh eccentricity distribution of width ${\sigma }_e$ of 0.045 and a typical sin(i) x Gaussian inclination distribution with a width ${\sigma }_i$ of 14 +/- 2 degrees. However, these distributions are only marginally acceptable. This is likely because, even after accounting for survey detection biases, the known large Hr < 8 and small Hr >= 8 Neptune Trojans appear to have markedly different eccentricities and inclinations. We propose that like the classical Kuiper belt, the stable intrinsic Neptunian Trojan population have dynamically `hot' and dynamically `cold' components to its eccentricity/inclination distribution, with ${\sigma }_{e-cold}$ ~ 0.02 / ${\sigma }_{i-cold}$ ~ 6${}^{\circ }$ and ${\sigma }_{e-hot}$~ 0.05 / ${\sigma }_{i-hot}$ ~ 18${}^{\circ }$. In this scenario, the `cold' L4 Neptunian Trojan population lacks the Hr >= 8 members and has 13 +11/-6 `cold' Trojans with Hr < 8. On the other hand, the `hot' L4 Neptunian Trojan population has 136 +57/-48 Trojans with Hr < 10 -- a population 2.4 times greater than that of the L4 Jovian Trojans in the same luminosity range.

arXiv comment15 pages, 7 figures, v3, accepted for publication in Icarus

References in corpus (50)

• The u'g'r'i'z' Standard Star Network
• The Pan-STARRS1 Surveys
• The Size Distribution of Trans-Neptunian Bodies
• The Canada-France Ecliptic Plane Survey - Full Data Release: The orbital structure of the Kuiper belt
• The Absolute Magnitude Distribution of Kuiper Belt Objects
• The Resonant Transneptunian Populations
• OSSOS. VII. 800+ trans-Neptunian objects - the complete data release
• On the Size-Dependence of the Inclination Distribution of the Main Kuiper Belt
• Orbit Fitting and Uncertainties for Kuiper Belt Objects
• The Phase Space Structure Near Neptune Resonances in the Kuiper Belt
• A Signature of Planetary Migration: The Origin of Asymmetric Capture in the 2:1 Resonance
• The Outer Solar System Origins Survey: I. Design and First-Quarter Discoveries
• On the origin of the Trojan asteroids: Effects of Jupiter's mass accretion and radial migration
• OSSOS VI. Striking Biases in the detection of large semimajor axis Trans-Neptunian Objects
• A carefully characterised and tracked Trans-Neptunian survey, the size-distribution of the Plutinos and the number of Neptunian Trojans
• The Capture of Centaurs as Trojans
• Origin and Dynamical Evolution of Neptune Trojans - I: Formation and Planetary Migration
• OSSOS III - Resonant Trans-Neptunian Populations: Constraints from the first quarter of the Outer Solar System Origins Survey
• Unbiased Inclination Distributions for Objects in the Kuiper Belt
• A Possible Divot in the Size Distribution of the Kuiper Belt's Scattering Objects
• OSSOS. VIII. The Transition Between Two Size Distribution Slopes in the Scattering Disk
• A Uranian Trojan and the frequency of temporary giant-planet co-orbitals
• Discovery of A New Retrograde Trans-Neptunian Object: Hint of A Common Orbital Plane for Low Semi-Major Axis, High Inclination TNOs and Centaurs
• The Canada-France Ecliptic Plane Survey (CFEPS) - High Latitude Component
• The Capture of Trojan Asteroids by the Giant Planets During Planetary Migration
• Origin and Dynamical Evolution of Neptune Trojans - II: Long Term Evolution
• The Size Distribution of the Neptune Trojans and the Missing Intermediate Sized Planetesimals
• Is the Missing Ultra-Red Material Colorless Ice?
• The Dynamics of Neptune Trojan: I. the Inclined Orbits
• 2001 QR322: a dynamically unstable Neptune Trojan?
• OSSOS II: A Sharp Transition in the Absolute Magnitude Distribution of the Kuiper Belt's Scattering Population
• The Intrinsic Neptune Trojan Orbit Distribution: Implications for the Primordial Disk and Planet Migration
• Trans-Neptunian objects found in the first four years of the Dark Energy Survey
• The Trojan Color Conundrum
• The 5:1 Neptune Resonance as Probed by CFEPS: Dynamics and Population
• OSSOS IX: two objects in Neptune's 9:1 resonance -- implications for resonance sticking in the scattering population
• Dynamical Classification of Trans-Neptunian Objects Detected by the Dark Energy Survey
• 2008 LC18: a potentially unstable Neptune Trojan
• Observation of Two New L4 Neptune Trojans in the Dark Energy Survey Supernova Fields
• 2011 HM102: Discovery of a High-Inclination L5 Neptune Trojan in the Search for a post-Pluto New Horizons Target
• Neptune Trojans and Plutinos: colors, sizes, dynamics, and their possible collisions
• OSSOS XVIII: Constraining migration models with the 2:1 resonance using the Outer Solar System Origins Survey
• A dwarf planet class object in the 21:5 resonance with Neptune
• The Pan-STARRS 1 Discoveries of five new Neptune Trojans
• Four temporary Neptune co-orbitals: (148975) 2001 XA255, (310071) 2010 KR59, (316179) 2010 EN65, and 2012 GX17
• Trailing (L5) Neptune Trojans: 2004 KV18 and 2008 LC18
• A Dearth of Small Members in the Haumea Family Revealed by the OSSOS Survey
• A Big Sky Approach to Cadence Diplomacy
• A Northern Ecliptic Survey for Solar System Science
• 2001 QR${}_{322}$ - an update on Neptune's first unstable Trojan companion

Cited by in corpus (4)

• Tuning the Legacy Survey of Space and Time (LSST) Observing Strategy for Solar System Science
• Keck, Gemini, and Palomar 200-inch visible photometry of red and very-red Neptunian Trojans
• OSSOS: XXVII. Population Estimates for Theoretically Stable Centaurs Between Uranus and Neptune
• NSF-DOE Vera C. Rubin Observatory's First View of the Neptune Trojan L5 (Trailing) Cloud: Two New Long-Term Stable Trojans