New features in the structure of the classical Kuiper Belt

Brett Gladman (1) , Michele T. Bannister (2) , Mike Alexandersen (3) , Ying-Tung Chen (3) , Stephen Gwyn (4) , J. J. Kavelaars (4) , Jean-Marc C. Petit (5) , Kathryn Volk (6) , Ossos Collaboration

1 UBC - University of British Columbia
2 UVIC - University of Victoria [Canada]
3 ASIAA - Academia Sinica Institute of Astronomy and Astrophysics
4 NRC - National Research Council of Canada
5 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)
6 University of Arizona

We report fascinating new dynamical structures emerging from a higher precision view of the classical Kuiper belt (the plentiful non-resonant orbits with semimajor axes in roughly the a=35-60 au range). The classical Kuiper Belt divides into multiple sub-populations: an 'inner' classical belt (a small group of non-resonant objects with a<39.4 au where the 3:2 resonance is located), an abundant 'main' classical belt (between the 3:2 and the 2:1 at a=47.4 au), and a difficult to study outer classical belt beyond the 2:1. We examine the dynamical structure, as precisely revealed in the detections from OSSOS (the Outer Solar System Origin's Survey); the data set is of superb quality in terms of orbital element and numbers of detections (Kavelaars et al, this meeting).The previous CFEPS survey showed that the main classical belt requires a complex dynamical substructure that goes beyond a simple 'hot versus cold' division based primarily on orbital inclination; the 'cold' inclination component requires two sub-components in the semimajor axis and perihelion distance q space (Petit et al 2011). CFEPS modelled this as a 'stirred' component present at all a=40-47 AU semimajor axes, with a dense superposed 'kernel' near a=44 AU at low eccentricity; the first OSSOS data release remained consistent with this (Bannister et al 2016). As with the main asteroid belt, as statistics and orbital quality improve we see additional significant substructure emerging in the classical belt's orbital distribution.OSSOS continues to add evidence that the cold stirred component extends smoothly beyond the 2:1 (Bannister et al 2016). Unexpectedly, the data also reveal the clear existence of a paucity of orbits just beyond the outer edge of the kernel; there are significantly fewer TNOs in the narrow semimajor axis band from a=44.5-45.0 AU. This may be related to the kernel population's creation, or it may be an independent feature created by planet migration as resonances moved in the primordial Kuiper Belt.

Domaines: Astrophysique [astro-ph]

Brett Gladman, Michele T. Bannister, Mike Alexandersen, Ying-Tung Chen, Stephen Gwyn, et al.. New features in the structure of the classical Kuiper Belt. DPS48, Oct 2016, Pasadena, United States. pp.113.07. ⟨hal-03563546⟩