An Overview of Asteroids and Near-Earth Objects

Asteroids are samples of the population of planetesimals which filled the early inner solar system and from which the terrestrial planets accreted. The asteroid fragments that fall to Earth as meteorites represent samples of at least 135 chemically distinct parent bodies. Following their formation, these parent bodies experienced a wide range of thermal histories from essentially unheated through complete melting. The meteorites are a very biased sample of main belt population, being dominated by parent bodies located near “escape hatches” (orbital resonances) in the main belt. The near-Earth asteroid / object (NEA, NEO) population suffers a similar but somewhat less severe bias. Care must be exercised in extrapolating the relative frequency of compositional and physical types among the meteorites to the NEO population. Understanding the suite of physical and chemical properties among the NEO population is critical to accessing the impact hazard and resource potential of these objects.https://commons.und.edu/ss-colloquium/1066/thumbnail.jp