OSSOS XVIII: Constraining migration models with the 2:1 resonance using the Outer Solar System Origins Survey

Abstract

Resonant dynamics plays a significant role in the past evolution and current state of our outer Solar System. The population ratios and spatial distribution of Neptune's resonant populations are direct clues to understanding the history of our planetary system. The orbital structure of the objects in Neptune's 2:1 mean-motion resonance (\emph{twotinos}) has the potential to be a tracer of planetary migration processes. Different migration processes produce distinct architectures, recognizable by well-characterized surveys. However, previous characterized surveys only discovered a few twotinos, making it impossible to model the intrinsic twotino population. With a well-designed cadence and nearly 100\% tracking success, the Outer Solar System Origins Survey (OSSOS) discovered 838 trans-Neptunian objects, of which 34 are securely twotinos with well-constrained libration angles and amplitudes. We use the OSSOS twotinos and the survey characterization parameters via the OSSOS Survey Simulator to inspect the intrinsic population and orbital distributions of twotino. The estimated twotino population, 4400${}_{-1100}^{+1500}$ with $H_r<8.66$ (diameter$\sim$100km) at 95\% confidence, is consistent with the previous low-precision estimate. We also constrain the width of the inclination distribution to a relatively narrow value of ${\sigma }_i$=6${}^{\circ }$${}_{-1}^{+1}$, and find the eccentricity distribution is consistent with a Gaussian centered on $e_{\mathrm{c}}=0.275$ with a width $e_{\mathrm{w}}=0.06$. We find a single-slope exponential luminosity function with $\alpha =0.6$ for the twotinos. Finally, we for the first time meaningfully constrain the fraction of symmetric twotinos, and the ratio of the leading asymmetric islands; both fractions are in a range of 0.2--0.6. These measurements rule out certain theoretical models of Neptune's migration history.

23 pages, 12 figures, 2 tables, accepted for publication in the Astronomical Journal

References in corpus (4)

• Origin of the Structure of the Kuiper Belt during a Dynamical Instability in the Orbits of Uranus and Neptune
• Tracking Neptune's Migration History through High-Perihelion Resonant Trans-Neptunian Objects
• The orbital distribution of trans-Neptunian objects beyond 50 au
• Details of Resonant Structures Within a Nice Model Kuiper Belt: Predictions for High-Perihelion TNO Detections

Cited by in corpus (2)

• OSSOS XX: The Meaning of Kuiper Belt Colors
• GLISSE: A GPU-optimized planetary system integrator with application to orbital stability calculations