The main asteroid belt, which inhabits a relatively narrow annulus 2.1-3.3 au from the Sun, contains a surprising diversity of objects ranging from primitive ice-rock mixtures to igneous rocks. The standard model used to explain this assumes that most asteroids formed in situ from a primordial disk that experienced radical chemical changes within this zone. Here we show that the violent dynamical evolution of the giant-planet orbits required by the so-called Nice model leads to the insertion of primitive trans-Neptunian objects into the outer belt. This result implies that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk. The dark captured bodies, composed of organic-rich materials, would have been more susceptible to collisional evolution than typical main-belt asteroids. Their weak nature makes them a prodigious source of micrometeoritessufficient to explain why most are primitive in composition and are isotopically different from most macroscopic meteorites. © 2009 Macmillan Publishers Limited. All rights reserved.
CITATION STYLE
Levison, H. F., Bottke, W. F., Gounelle, M., Morbidelli, A., Nesvorný, D., & Tsiganis, K. (2009). Contamination of the asteroid belt by primordial trans-Neptunian objects. Nature, 460(7253), 364–366. https://doi.org/10.1038/nature08094
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