FIGURE 1. The orbital element distributions of real and modelled asteroids.

From the following article:

Contamination of the asteroid belt by primordial trans-Neptunian objects

Harold F. Levison, William F. Bottke, Matthieu Gounelle, Alessandro Morbidelli, David Nesvorný & Kleomenis Tsiganis

Nature 460, 364-366(16 July 2009)



The distributions of eccentricity, e (a), and inclination, i (b), as functions of semi-major axis, a, of asteroids in Hilda (objects which orbit in the 2:3 mean-motion resonance with Jupiter near 3.9 au), Trojan and main-belt populations. The small green pluses show all the numbered objects with diameters greater than 40 km (the asteroid belt is probably complete at these sizes) in the International Astronomical Union's Minor Planet Center database. We calculated the diameters from published absolute magnitudes, assuming the albedos (Supplementary Information, section S2.1). The black symbols show the D-type asteroids as catalogued in refs 11 and 12. It is important to note that asteroid (336) Lacadiera, at a = 2.25 au, e = 0.1 and i = 5.6°, which is classified as a D-type in ref. 11, has an unusual spectrum (H. Campins, personal communication), and thus is probably a different type of object. We therefore use a smaller symbol to plot the location of this object and did not include it in our analysis. We only include D-type asteroids here because it is difficult to distinguish P-types from other, more processed, asteroids, with the result that the catalogue of P-types probably suffers from significant contamination30. The red dots show the location of objects captured during our simulations. The main result of our simulations is that, in addition to the resonant asteroids, a significant number of objects are trapped in the outer main belt (OMB). Unfortunately, it is not possible to perform a direct comparison between the orbital element distribution of our trapped objects and that of the D-types because the observations are biased owing to selection criteria, asteroid families and the like. However, we find noteworthy the fact that the inner edge of each populations is at a approximately 2.6 au.

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