title: What can meteorites tell us about nebular conditions and processes during planetesimal accretion?
abstract: Analysis of the most primitive meteorites can yield detailed information about environmental conditions and physical/chemical processes in the earliest Solar System, including the nebular stage during which planetesimals were accreted.  Such information pertains to time scales, thermal and chemical evolution, inhomogeneity and mixing, magnetic fields, and grain growth in the solar nebula.  Nebular processes identified include evaporation, condensation, localized melting, and fractionation both of solids from gas and among different solids.  Little direct evidence remains even in primitive meteorites of the actual accretion process.  The absence of intrinsic factors capable of enhancing accretion among meteoritic constituents suggests that gravitational instabilities might have been important in promoting planetesimal accretion.
authors.affiliation: Institute of Geophysics, University of California, Los Angeles 90024-1567, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Kerridge
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D004602:Elements; D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D007554:Isotopes; D008280:Magnetics; D019110:Meteoroids; D018543:Minor Planets; D010084:Oxidation-Reduction; D010316:Particle Size; D016082:Solar System; D013696:Temperature
chemical_list: D004602:Elements; D007554:Isotopes