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Book Sections Year : 2017

Composition of Solar System Small Bodies


Small bodies in our stellar system are rocky and/or icy objects, usually ranging in size from a few meters to a few hundreds of kilometers. They comprise main belt asteroids, giant planet Trojans, trans-neptunian objects (TNOs), and comets. Their physical nature, distribution, formation, and evolution are fundamental to understanding how the solar system formed, evolved, and ultimately, why water and life are present on Earth. In the present-day solar system, they are the most direct remnants of the original building blocks that formed the terrestrial planets and the solid cores of the giant planets. As such, they contain a relatively pristine record of the initial conditions that existed in our solar nebula some 4.6 Gyr ago. The small bodies that have survived since that epoch, however, have experienced numerous collisional, dynamical, and thermal events that have shaped their present-day physical and orbital properties. Interpreting this record via observations, laboratory studies, and theoretical/numerical modeling can tell us much about the primordial state of these bodies and how they have evolved thereafter. In fact, even though small bodies represent only a tiny fraction of the total mass of the planets, their large numbers, diverse compositions, and orbital distributions provide powerful constraints for planetary system formation models (Bottke et al., 2002). Observations of the solar system small bodies performed mainly between the early 1970s and today led to the determination of orbits as well as the characterization of the visible and near-infrared spectral propeties, sizes, and albedos for (i) a statistically significant sample of small bodies up to 5 AU and (ii) a restricted number of small bodies beyond 5 AU. Inter alia, these datasets have allowed us to reach a preliminary understanding of the compositional distribution across the different populations of small bodies and of the architecture of our solar system.

Dates and versions

hal-02347139 , version 1 (02-11-2021)



Pierre Vernazza, Pierre Beck. Composition of Solar System Small Bodies. Planetesimals: Early Differentiation and Consequences for Planets, 2017, ⟨10.1017/9781316339794.013⟩. ⟨hal-02347139⟩
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