OSSOS. IX. Two Objects in Neptune's 9:1 Resonance—Implications for Resonance Sticking in the Scattering Population

Journal Article · Fri Jun 01 04:00:00 EDT 2018 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AAC268· OSTI ID:22897491

Volk, Kathryn ^[1]; Murray-Clay, Ruth A. ^[2]; Gladman, Brett J. ^[3]; Lawler, Samantha M.; Gwyn, Stephen D. J.; Kavelaars, J. J. ^[4]; Yu, Tze Yeung Mathew ^[5]; Alexandersen, Mike; Ying-Tung, Chen ^[6]; Bannister, Michele T. ^[7]; Dawson, Rebekah I. ^[8]; Greenstreet, Sarah ^[9]; Wen, Lin Hsing ^[10]; Lykawka, Patryk Sofia ^[11]; Petit, Jean-Marc ^[12]

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1. Lunar and Planetary Laboratory, University of Arizona, 1629 E University Boulevard, Tucson, AZ 85721 (United States)
2. Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
3. Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)
4. NRC-Herzberg Astronomy and Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, British Columbia V9E 2E7 (Canada)
5. Department of Physics and Astronomy, University of California, Los Angeles, CA (United States)
6. Institute of Astronomy and Astrophysics, Academia Sinica, 11F of AS/NTU Astronomy-Mathematics Building, Nr. 1 Roosevelt Road, Sec. 4, Taipei 10617, Taiwan, R.O.C. (China)
7. Astrophysics Research Centre, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom)
8. Department of Astronomy and Astrophysics, Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States)
9. Las Cumbres Observatory, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States)
10. Institute of Astronomy, National Central University, Taoyuan 32001, Taiwan (China)
11. School of Interdisciplinary Social and Human Sciences, Kindai University (Japan)
12. Institut UTINAM UMR6213, CNRS, Univ. Bourgogne Franche-Comté, OSU Theta F25000 Besançon (France)

We discuss the detection in the Outer Solar System Origins Survey (OSSOS) of two objects in Neptune’s distant 9:1 mean motion resonance at semimajor axis a ≈ 130 au. Both objects are securely resonant on 10 Myr timescales, with one securely in the 9:1 resonance’s leading asymmetric libration island and the other in either the symmetric or trailing asymmetric island. These objects are the largest semimajor axis objects with secure resonant classifications, and their detection in a carefully characterized survey allows for the first robust resonance population estimate beyond 100 au. The detection of these objects implies a 9:1 resonance population of 1.1 × 10{sup 4} objects with H {sub r} < 8.66 (D ≳ 100 km) on similar orbits (95% confidence range of ∼(0.4–3) × 10{sup 4}). Integrations over 4 Gyr of an ensemble of clones spanning these objects’ orbit-fit uncertainties reveal that they both have median resonance occupation timescales of ∼1 Gyr. These timescales are consistent with the hypothesis that these objects originate in the scattering population but became transiently stuck to Neptune’s 9:1 resonance within the last ∼1 Gyr of solar system evolution. Based on simulations of a model of the current scattering population, we estimate the expected resonance sticking population in the 9:1 resonance to be 1000–4500 objects with H {sub r} < 8.66; this is marginally consistent with the OSSOS 9:1 population estimate. We conclude that resonance sticking is a plausible explanation for the observed 9:1 population, but we also discuss the possibility of a primordial 9:1 population, which would have interesting implications for the Kuiper Belt’s dynamical history.

• OSTI ID: 22897491
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 6 Vol. 155; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASYMMETRY
COMPUTERIZED SIMULATION
HYPOTHESIS
RESONANCE
SOLAR SYSTEM EVOLUTION
SYMMETRY