A CAREFULLY CHARACTERIZED AND TRACKED TRANS-NEPTUNIAN SURVEY: THE SIZE DISTRIBUTION OF THE PLUTINOS AND THE NUMBER OF NEPTUNIAN TROJANS
- Department of Physics and Astronomy, 6224 Agricultural Road, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)
- National Research Council of Canada, Victoria, BC V9E 2E7 (Canada)
- Institut UTINAM, CNRS-UMR 6213, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France)
- Department of Physics and Astronomy, University of Victoria, Victoria, BC (Canada)
The trans-Neptunian objects (TNOs) preserve evidence of planet building processes in their orbital and size distributions. While all populations show steep size distributions for large objects, a relative deficit of Neptunian trojans and scattering objects with diameters of D < 100 km has been detected. We investigated this deficit with a 32 square degree survey, in which we detected 77 TNOs that are brighter than a limiting r-band magnitude of 24.6. Our plutino sample (18 objects in 3:2 mean-motion resonance with Neptune) shows a deficit of D < 100 km objects, rejecting a single power-law size distribution at >99% confidence. Combining our survey with the Canada–France Ecliptic Plane Survey, we perform a detailed analysis of the allowable parameters for the plutino size distribution, including knees and divots. We surmise the existence of 9000 ± 3000 plutinos with an absolute magnitude of H {sub r} ≤ 8.66 and 37000{sub −10000}{sup +12000} with H {sub r} ≤ 10.0 (95% confidence). Our survey also discovered one temporary Uranian trojan, one temporary Neptunian trojan, and one stable Neptunian trojan, for which we estimate populations of 110{sub −100}{sup +500}, 210{sub −200}{sup +900}, and 150{sub −140}{sup +600} with H {sub r} ≤ 10.0, respectively. All three populations are thus less numerous than the main belt asteroids (592 asteroids with H {sub r} ≤ 10.0). With such population sizes, the temporary Neptunian trojans cannot be previously stable trojans diffusing out of the resonance now; they must be recently captured Centaurs or scattering objects. As the bias against the detection of objects grows with larger semimajor axes, our discovery of three 3:1 resonators and one 4:1 resonator adds to the growing evidence that the high-order resonances are far more populated than is typically predicted.
- OSTI ID:
- 22862858
- Journal Information:
- The Astronomical Journal (Online), Vol. 152, Issue 5; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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