Early impact history and dynamical origin of differentiated meteorites and asteroids

Edward R.D. Scott, Klaus Keil, Joseph I. Goldstein, Erik Asphaug, William F. Bottke, Nicholas A. Moskovitz

Research output: Chapter in Book/Report/Conference proceedingChapter

8 Scopus citations

Abstract

Differentiated asteroids and igneous meteorites present numerous challenges to our understanding of the impact and dynamical evolution of asteroids and meteorite parent bodies. Igneous meteorites, including irons, achondrites, and stony-iron meteorites, testify to the prior existence of ~100 differentiated bodies. Destruction of these bodies by hypervelocity impact over 4 G.y. would have required numerous giant impacts, although this is inconsistent with the preservation of Vesta’s basaltic crust and the lack of differentiated asteroid families. We review recent advances in elucidating the early chronology of meteorites, spectroscopic observations of likely differentiated asteroids, petrological studies of differentiated meteorites, impact disruption of differentiated planetesimals during accretion, and dynamical scenarios for capturing material into the asteroid belt. Together, these advances suggest a new paradigm in which planetesimals accreted rapidly in the inner solar system and were melted by 26Al less than 2 m.y. after the formation of calcium-aluminum-rich inclusions (CAIs). While molten they were disrupted by grazing hit-and-run impacts during the accretion of planetesimals. Later, when still hot, the survivors were disrupted by hypervelocity impacts. Impact debris from the differentiated bodies was transferred from the newly formed terrestrial planet region to stable orbits in the asteroid belt. This evolutionary history leaves many questions unanswered but suggests new paths for future exploration of the asteroid belt and petrological and isotopic studies of meteorites.

Original languageEnglish (US)
Title of host publicationAsteroids IV
PublisherUniversity of Arizona Press
Pages573-595
Number of pages23
ISBN (Electronic)9780816532186
ISBN (Print)9780816532131
StatePublished - Jan 1 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Scott, E. R. D., Keil, K., Goldstein, J. I., Asphaug, E., Bottke, W. F., & Moskovitz, N. A. (2015). Early impact history and dynamical origin of differentiated meteorites and asteroids. In Asteroids IV (pp. 573-595). University of Arizona Press.