Thermal histories of chondrules in solar nebula shocks

M. A. Morris, Steven Desch

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Chondrules are important early Solar System materials that can provide a wealth of information on conditions in the solar nebula, if their formation mechanism can be understood. The theory most consistent with observational constraints, especially thermal histories, is the so-called shock model, in which chondrules were melted in solar nebula shocks. However, several problems have been identified with previous shock models. These problems all pertained to the treatment of the radiation field, namely, the input boundary condition to the radiation field, the proper treatment of the opacity of solids, and the proper treatment of molecular line cooling. In this paper, we present the results of our updated shock model, which corrects for the problems listed above. Our new hydrodynamic shock code includes a complete treatment of molecular line cooling due to H2O. Previously, shock models including line cooling predicted chondrule cooling rates exceeding 105 K hr-1. Contrary to these expectations, we have found that the effect of line cooling is minimal; after the inclusion of line cooling, the cooling rates of chondrules are 10-1000 K hr-1. The reduction in the otherwise rapid cooling rates attributable to line cooling is due to a combination of factors, including buffering due to hydrogen recombination/ dissociation, high column densities of water, and backwarming. Our model demonstrates that the shock model for chondrule formation remains consistent with observational constraints.

Original languageEnglish (US)
Pages (from-to)1474-1494
Number of pages21
JournalAstrophysical Journal
Volume722
Issue number2
DOIs
StatePublished - Oct 20 2010

Keywords

  • Meteorites, meteors, meteoroids
  • Protoplanetary disks
  • Radiative transfer shock waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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