A Carefully Characterized and Tracked Trans-Neptunian Survey: The Size distribution of the Plutinos and the Number of Neptunian Trojans
Abstract
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 r ≤ 8.66 and {37000}-10000+12000 with H 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}-100+500, {210}-200+900, and {150}-140+600 with H r ≤ 10.0, respectively. All three populations are thus less numerous than the main belt asteroids (592 asteroids with H 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.
- Publication:
-
The Astronomical Journal
- Pub Date:
- November 2016
- DOI:
- 10.3847/0004-6256/152/5/111
- arXiv:
- arXiv:1411.7953
- Bibcode:
- 2016AJ....152..111A
- Keywords:
-
- astrometry;
- Kuiper belt: general;
- methods: data analysis;
- methods: observational;
- planets and satellites: detection;
- surveys;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 56 pages, 10 figures, 4 tables